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A174428 Triangle read by rows: R(n,k)= sigma(n) mod k, where sigma(.) is the sum of divisors. 1
0, 0, 1, 0, 0, 1, 0, 1, 1, 3, 0, 0, 0, 2, 1, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 3, 2, 1, 0, 1, 0, 3, 0, 3, 1, 7, 0, 1, 1, 1, 3, 1, 6, 5, 4, 0, 0, 0, 2, 3, 0, 4, 2, 0, 8, 0, 0, 0, 0, 2, 0, 5, 4, 3, 2, 1, 0, 0, 1, 0, 3, 4, 0, 4, 1, 8, 6, 4, 0, 0, 2, 2, 4, 2, 0, 6, 5, 4, 3, 2, 1, 0, 0, 0, 0, 4, 0, 3, 0, 6, 4, 2, 0, 11, 10 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,10

LINKS

Table of n, a(n) for n=1..105.

EXAMPLE

The triangle starts in row n=1 with columns 1<=k<=n as:

0;

0,1;

0,0,1;

0,1,1,3;

0,0,0,2,1;

0,0,0,0,2,0;

0,0,2,0,3,2,1;

MATHEMATICA

Flatten[Table[Mod[DivisorSigma[1, n], k], {n, 20}, {k, n}]] (* Harvey P. Dale, Apr 17 2014 *)

CROSSREFS

Cf. A000203, A154234.

Sequence in context: A242434 A036873 A081130 * A308347 A090225 A206705

Adjacent sequences:  A174425 A174426 A174427 * A174429 A174430 A174431

KEYWORD

nonn,tabl

AUTHOR

Juri-Stepan Gerasimov, Nov 28 2010

STATUS

approved

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Last modified October 26 20:42 EDT 2021. Contains 348269 sequences. (Running on oeis4.)