Thursday, May 9, 2024

A362058 Contributions to OEIS

 


A362058The location of the first occurrence of n in the decimal expansion of phi (the golden ratio, 1.6180339887...).0
4, 0, 19, 5, 11, 22, 1, 10, 3, 7, 231, 34, 121, 55, 254, 366, 0, 35, 2, 188, 19, 54, 62, 131, 78, 213, 67, 63, 51, 174, 40, 137, 181, 5, 26, 56, 28, 98, 32, 6, 105, 90, 347, 27, 58, 21, 70, 102, 15, 11, 214, 394, 66, 111, 57, 768, 30, 48, 22, 166, 68, 1, 50 (listgraphrefslistenhistoryedittextinternal format)
OFFSET
0,1
COMMENTS
Locations in the expansion of phi are numbered 0 for the digit before the decimal point, 1 for the first digit after the decimal point, and so on.
LINKS
FORMULA
a(n) = A088577(n) - 1.
EXAMPLE
The first occurrence of 0 in phi occurs 4 places after the decimal point, so a(0)=4; 5 first occurs 22 places after the decimal point, so a(5)=22; 10 first occurs 231 places after the decimal point so a(10)=231.
MATHEMATICA
Table[-1 + SequencePosition[#, IntegerDigits@ n][[1, 1]], {n, 0, 50}] &@ First@ RealDigits@ N[GoldenRatio, 10^4]
CROSSREFS
Cf. A001622 (phi)
Cf. A088577 (1-based locations).
Cf. A078197 (for e), A176341 (for Pi), A014777 (for Pi but different indexing).
Sequence in context: A058348 A184946 A351615 * A085618 A263626 A282579
KEYWORD
nonn,base
AUTHOR
James C. McMahon, Apr 06 2023
STATUS
approved

Contributions to The On-Line Encyclopedia of Integer Sequences A361746

 I'm making this post to have a place to go to quickly reference OEIS sequences that I have authored.

A361746Number of occurrences of the most frequently occurring letter(s) in US English name of n.0
1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 3, 2, 2, 2, 2, 2, 4, 3, 3, 2, 2, 3, 3, 2, 2, 2, 3, 3, 3, 2, 2, 3, 3, 2, 2, 2, 2, 3, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 2, 2, 2, 2, 1, 1, 2, 2, 1, 2, 2, 2, 2, 2, 2, 3, 2, 4, 2, 3, 2, 4, 3, 3, 1, 2, 2, 3, 1, 2, 2, 3, 2, 2, 2, 3, 2, 3, 2, 2, 2, 3, 2, 4, 2 (listgraphrefslistenhistoryedittextinternal format)
OFFSET
0,4
LINKS
EXAMPLE
For n = 3, a(3) = 2 because the letter e occurs twice in the word "three".
For n = 4, a(4) = 1 because the letters f, o, u and r each occur once in the word "four".
MATHEMATICA
a[n_] := Max[Values[LetterCounts[IntegerName[n, "Words"]]]]; Array[a, 100, 0] (* Amiram Eldar, Mar 24 2023 *)
PROG
(Python)
from num2words import num2words
from collections import Counter
def a(n): return max(Counter(num2words(n).replace(" and", "").replace(" ", "")).values())
print([a(n) for n in range(112)]) # Michael S. Branicky, Mar 24 2023
CROSSREFS
Cf. A005589.
Sequence in context: A156775 A064693 A325614 * A369917 A319608 A230850
KEYWORD
easy,nonn,word,less
AUTHOR
James C. McMahon, Mar 22 2023
STATUS
approved                                                                                







Wednesday, April 3, 2024

Are Prime Numbers Predictable?


A recent paper by Han-Linn Li, Shu-Cherng Fang, and Way Kuo of the Department of Computer Science, City University of Hong Kong, suggests that there are cyclic effects among the composites, spawning primes distributed periodically. A link to their paper is given here:  The Periodic Table of Primes.

I'm still reading it now, so I will post more later. Meanwhile, I wanted to share it immediately.

Update: The idea proposed by the paper is that the authors identify 48 integers as "roots." These integers are between 11 and 211, and are either prime or not divisible by 2, 3, 5 or 7. The periodic cycle claimed is 210 which is the product of 2, 3, 5 and 7. 

I recently came across a criticism of the paper which I'm linking here: A New Study About Prime Numbers Is Stirring Up a Mess of Controversy.

An Open Message to the Blog's Fans in Singapore

(Image:  Free 12 singapore icons - Iconfinder ) This past week, more views of this blog were made from Singapore than other country. To ackn...

Popular in last 30 days