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.

A378481 Integers k such that A378414(k) == k (mod A066417(k)).

Original entry on oeis.org

33, 77, 153, 372, 1540, 2300, 2692, 2736, 7812, 8721, 12593, 26025, 26481, 27972, 39321, 64009, 104409, 175441, 325180, 335616, 422593, 455625, 564376, 575040, 756460, 800073, 1104521, 2180545, 2304332, 3502665, 3691968, 5130909, 5515121, 9331441, 9546265
Offset: 1

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Author

Paolo P. Lava, Nov 28 2024

Keywords

Comments

Also integers k such that A000217(k) == k (mod A066417(k)).
So far, only 33 belongs both to A232538 and A378414.

Examples

			Antidivisors of 77 are 2, 3, 5, 9, 14, 17, 22, 31, 51 and their sum is 154.
Then 77*78/2 mod 154 = 3003 mod 154 = 77.
		

Crossrefs

Programs

  • Maple
    with(numtheory): P:=proc(q) local j,k,n,v; v:=[];
    for n from 3 to q do k:=0; j:=n; while j mod 2<>1 do k:=k+1; j:=j/2; od;
    if n*(n+1)/2 mod (sigma(2*n+1)+sigma(2*n-1)+sigma(n/2^k)*2^(k+1)-6*n-2)=n
    then v:=[op(v),n]; fi; od; op(v); end: P(10^5);