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.

A340541 Primes p such that the product of (p mod q) for primes q < p is a multiple of the sum of (p mod q) for primes q < p.

Original entry on oeis.org

3, 11, 17, 31, 59, 67, 73, 101, 103, 173, 179, 193, 199, 211, 223, 349, 401, 463, 491, 499, 557, 563, 569, 571, 577, 587, 607, 613, 619, 631, 673, 709, 751, 757, 769, 797, 809, 857, 859, 877, 911, 919, 929, 967, 1009, 1033, 1039, 1049, 1151, 1153, 1193, 1201, 1237, 1249, 1259, 1289, 1297, 1303
Offset: 1

Views

Author

J. M. Bergot and Robert Israel, Jan 11 2021

Keywords

Comments

Primes prime(n) such that A102647(n) is divisible by A033955(n).

Examples

			a(3) = 17 is a term since (17 mod q) for primes q=2,3,5,7,11,13 are 1,2,2,3,6,4, and 1*2*2*3*6*4 = 288 is divisible by 1+2+2+3+6+4 = 18.
		

Crossrefs

Programs

  • Maple
    P:= [seq(ithprime(i),i=1..1000)]:
    filter:= proc(n) local L,k;
      L:= [seq(P[n] mod P[k],k=1..n-1)];
      convert(L,`*`) mod convert(L,`+`) = 0
    end proc:
    S:=select(filter, [$2..1000]):
    map(t -> P[t], S);
  • PARI
    isok(p) = {if (isprime(p) && (p>2), my(s=0, t=1); forprime(q=2, p-1, my(x= p%q); s += x; t *= x;); !(t % s););} \\ Michel Marcus, Jan 11 2021