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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. 2
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 11 13:41 EDT 2021. Contains 343791 sequences. (Running on oeis4.)