cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A302867 a(n) is the sum of remainders n mod p, over primes p for which n falls between p and p+p^2.

Original entry on oeis.org

0, 0, 1, 1, 3, 1, 3, 6, 6, 4, 7, 8, 11, 8, 7, 11, 15, 20, 25, 26, 25, 20, 26, 33, 35, 29, 36, 36, 43, 46, 53, 61, 58, 49, 50, 58, 66, 56, 52, 61, 70, 73, 83, 83, 94, 82, 93, 105, 110, 122, 117, 116, 128, 141, 143, 149, 142, 125, 137, 150, 163, 146, 160, 174
Offset: 1

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Author

Meir-Simchah Panzer, May 06 2018

Keywords

Comments

"Jubilees". Motivation: 7 years are counted 7 times and capped off with a 50th year, the Jubilee (Leviticus 25:8); similarly, 7 days are counted 7 times and capped off with "Chag ha-Atzeret" (The Festival of Stopping) in the Omer-counting cycle (ibid 23:15); and these iterative cycles overlay other iterative cycles, like the lunar cycle nested not-quite-evenly within the solar year. This sequence idealizes the overlaying of multiple cycles. Each prime p generates a "swell" of p waves each with max amplitude = p-1, a kind of wavelet that is added into the total signal that is the sequence (e.g., the swell generated by 3 is (3^2)+1 terms in length, running for n=3,...,12 and has values n mod 3 = 0,1,2,0,1,2,0,1,2,0).

Examples

			For n = 12, we sum over primes 3, 5, 7, 11: a(12) = 12 mod 3 + 12 mod 5 + 12 mod 7 + 12 mod 11 = 0 + 2 + 5 + 1 = 8. In contrast with A024934, the sum does not include 12 mod 2 since 12 > 2+2^2.
		

Crossrefs

Similar to A024934, but waves generated by primes are wavelets.

Programs

  • PARI
    a(n) = sum(k=1, n, (n % k)*isprime(k)*(n <= (k^2+k))); \\ Michel Marcus, May 14 2018

Formula

a(n) = Sum_{primes p, sqrt(n) - 1/2 < p <= n} (n mod p).