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A272720 Where records occur in A054025. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 12 16:55 EDT 2021. Contains 344959 sequences. (Running on oeis4.)