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Tuesday, February 25, 2025
A381149 Contribution to the OEIS
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Thursday, February 20, 2025
A381150 Contribution to the OEIS
Recently proposed for the On-Line Encyclopedia of Integer Sequences (OEIS) is the sequence:
a(1) = 2, a(2) = 3; thereafter, a(n) = a(n-1) + (sum of prior prime terms or whose negatives are prime) - (sum of prior composite terms or whose negatives are composite).
The sequence starts: 2, 3, 8, 5, 7, 16, 9, -7, -30, -23, -39, -16, 23, 85, 62, -23, -131... and continues to cycle through negative and positive integers. Although the sequence is not periodic, it does repeat terms. For example, the term 347 (or its negative) occurs nine times in the first 48 terms. The 418th (or its negative) occurs 71 times in a span of 211 terms.
My colleague, Michael De Vlieger, produced the graphic showing the sequence's progression shown above.
If approved, the sequence will become A381150. Currently, it is still in draft form: https://oeis.org/A381150.
Update: The sequence was published 2/25/2025.

Monday, February 17, 2025
Using Excel Solver to Find the Solution to a Geometry Puzzle

Saturday, February 1, 2025
Project Euler - Part 2

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