A134188 - OEIS

A134188

a(0)=1. a(n) = the sum of the terms of the sequence (from among terms a(0) through a(n-1)) which equal any "non-isolated divisors" of (2n). A divisor, k, of n is non-isolated if (k-1) or (k+1) also divides n.

1, 1, 2, 4, 4, 4, 16, 4, 4, 4, 28, 4, 32, 4, 4, 4, 4, 4, 52, 4, 56, 4, 4, 4, 68, 4, 4, 4, 4, 4, 88, 4, 4, 4, 4, 4, 108, 4, 4, 4, 120, 4, 124, 4, 4, 4, 4, 4, 144, 4, 148, 4, 4, 4, 160, 4, 4, 4, 4, 4, 180, 4, 4, 4, 4, 4, 200, 4, 4, 4, 212, 4, 216, 4, 4, 4, 4, 4, 236, 4, 240, 4, 4, 4, 252, 4, 4, 4

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..87.

EXAMPLE

The positive divisors of 2*12=24 are 1,2,3,4,6,8,12,24. Of these, 1,2,3,4 are the non-isolated divisors of 24. There are 2 terms among the earlier terms of the sequence that equal 1, 1 term that equals 2, 0 terms that equal 3 and 7 terms that equal 4. So a(12) = 2*1 +1*2 + 0*3 +7*4 = 32.

CROSSREFS

Cf. A134187.

Sequence in context: A332336 A101449 A221564 * A140295 A291780 A070529

Adjacent sequences: A134185 A134186 A134187 * A134189 A134190 A134191

KEYWORD

nonn

AUTHOR

Leroy Quet, Oct 12 2007

EXTENSIONS

Extended by Ray Chandler, Jun 25 2008

STATUS

approved