Thursday, September 26, 2024

Happy Anniversary Rule 30


(Image: By Richard Ling - Own work; Location: Cod Hole, Great Barrier Reef, Australia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=293495)

This year my wife and I are celebrating our 40th anniversary. This year Stephen Wolfram also celebrates the 40th anniversary of his favorite scientific discovery as he wrote in My All-Time Favorite Science Discovery

Also, see a prior post -https://www.blogger.com/blog/post/edit/8711601538345502519/636715033944644578.

This discovery led to Wolfram's publication of A New Kind of Science (now available online).



Friday, September 13, 2024

A375508 Contribution to the OEIS

 

A375508Begin A160649 with n instead of 2; a(n) is the position in the new sequence at which it generates the same numbers as A160649 or a(n)=0 if it doesn't.0
1, 1, 1, 2, 1, 2, 1, 2, 2, 1, 1, 5, 4, 1, 3, 1, 1, 3, 2, 1, 2, 1, 1, 6, 2, 5, 1, 5, 4, 1, 1, 3, 3, 2, 2, 1, 1, 5, 1, 4, 3, 2, 1, 2, 2, 1, 1, 3, 2, 2, 5, 1, 1, 4, 2, 3, 1, 2, 1, 3, 2, 7, 1, 7, 6, 6, 5, 5, 1, 4, 3, 1, 1, 4, 1, 2, 3, 1, 1, 2, 9, 9, 8, 1, 8, 1, 7 (listgraphrefslistenhistoryedittextinternal format)
OFFSET
1,4
COMMENTS
The indices of the matching entries of A160649 and this sequence do not necessarily have to be the same (see Examples).
LINKS
Michael De Vlieger, Histogram of the frequency of a(n) = k, n = 1..2^20, k = 1..14. Maximum in the dataset is k = 41.
Michael De Vlieger, Histogram of the frequency of a(n) = k, n = 1..2^24, k = 1..14. Maximum in the dataset is k = 57.
Wikipedia, Kruskal count
EXAMPLE
Using () to indicate the point at which the new sequence generates the same numbers as A160649:
A160649: 2, 3, 4, 6, 8, 11, 12... a(1)=1
Start=3: (3), 4, 6, 8, 11, 12... a(2)=1
Start=4: (4), 6, 8, 11, 12, 15... a(3)=1
Start=5: 5, (6), 8, 11, 12, 15... a(4)=2
MATHEMATICA
Lim=88; pseq1=NestList[#+PrimeOmega[#]&, 2, Lim] (* pseq1 is base sequence A160649 *); pseq={}; Do[ i=1; s=n; While[!MemberQ[pseq1, s], s=s+PrimeOmega[s]; i++]; AppendTo[pseq, i], {n, 2, Lim}]; pseq (* pseq is A375508 *)
CROSSREFS
Cf. A160649.
Sequence in context: A326194 A331251 A309858 * A022921 A080763 A245920
KEYWORD
nonn,new
AUTHOR
James C. McMahon, Aug 18 2024
STATUS
approved

Additional work on this sequence is given in the post: https://jamesmacmath.blogspot.com/2024/08/kruskal-count-with-prime-omega.html

A375606 Contribution to the OEIS

A375606a(1) = 1; a(n+1) = a(n) + floor(harmonic mean of previous terms).0
1, 2, 3, 4, 5, 7, 9, 11, 14, 17, 20, 23, 27, 31, 35, 40, 45, 50, 55, 61, 67, 73, 80, 87, 94, 102, 110, 118, 126, 135, 144, 153, 163, 173, 183, 193, 204, 215, 226, 238, 250, 262, 275, 288, 301, 314, 328, 342, 356, 371, 386, 401, 417, 433, 449, 465, 482, 499, 516 (listgraphrefslistenhistoryedittextinternal format)
OFFSET
1,2
LINKS
EXAMPLE
a(6) = 5 + floor(harmonic mean(1,2,3,4,5)) = 5 + floor(300/377) = 7.
MATHEMATICA
Nest[Append[#, Last[#]+Floor@HarmonicMean[#]]&, {1}, 58]
CROSSREFS
Sequence in context: A274197 A286267 A337334 * A008750 A076677 A029001
KEYWORD
nonn,new
AUTHOR
James C. McMahon, Aug 20 2024
STATUS
approved

 

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