A272720 Where records occur in A054025.

1, 2, 8, 12, 80, 84, 144, 360, 960, 1680, 1800, 2880, 4800, 6300, 15600, 18480, 33600, 44352, 56700, 65520, 129600, 170100, 176400, 273600, 277200, 498960, 665280, 1146600, 1915200, 1940400, 2494800, 4127760, 8255520, 8482320, 13305600, 17236800, 20638800

Offset

1,2

Comments

The first values of sigma(a(n)) mod d(a(n)) are: 0, 1, 3, 4, 6, 8, 13, 18, 24, 32, 33, 36, 40, 50, 56, 64, 68, 72, 86, 96, 97, 104, 111, 122, 168, 176, 192, 198, 220, 252, 276, 288.

Links

Giovanni Resta, Table of n, a(n) for n = 1..68 (terms < 10^12)

Maple

with(numtheory): P:= proc(q) local a, n; a:=-1; for n from 1 to q do
if sigma(n) mod tau(n)>a then a:=sigma(n) mod tau(n); print(n);
fi; od; end: P(10^9);

Mathematica

Reap[r=-1; n=0; While[++n<10^5, m = Mod @@ DivisorSigma[ {1, 0}, n]; If[m > r, r=m; Sow@n ]]][[2, 1]] (* Giovanni Resta, May 06 2016 *)

Crossrefs

Cf. A000005, A000203, A049642, A054025.

Sequence in context: A176968 A308935 A126192 * A331459 A330816 A066471

Adjacent sequences: A272717 A272718 A272719 * A272721 A272722 A272723

Keyword

nonn

Author

Paolo P. Lava, May 05 2016

Extensions

a(33)-a(37) from Giovanni Resta, May 06 2016

Status

approved