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A111631 Inverse of A110412 or zero if none exists. 0
1, 2, 3, 5, 4, 17, 13, 6, 9, 8, 14, 0, 22, 26, 15, 401, 21, 12, 16, 0, 18, 20, 77, 226, 28, 65, 44, 626, 52, 32, 50, 125, 91, 24, 221, 404, 212, 42, 81, 45, 63, 40, 75, 66, 36, 56, 64, 338, 88, 104, 130, 153, 154, 152, 190, 328, 175, 48, 184, 245, 286, 182, 100, 105, 243 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A110412: Sum_{d<n is a divisor of n} tau(n-d).

Found zeros < 7500 only for 12 & 20.

LINKS

Table of n, a(n) for n=0..64.

MATHEMATICA

f[n_] := Plus @@ (DivisorSigma[0, n - # ] & /@ Most[Divisors[n]]); t = Table[0, {100}]; Do[a = f[n]; If[a < 100 && t[[a + 1]] == 0, t[[a + 1]] = n; Print[{a, n}]], {n, 630}]

CROSSREFS

Cf. A110412.

Sequence in context: A119745 A095753 A139537 * A235610 A118141 A175210

Adjacent sequences:  A111628 A111629 A111630 * A111632 A111633 A111634

KEYWORD

nonn

AUTHOR

Amarnath Murthy and Robert G. Wilson v, Aug 09 2005

STATUS

approved

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Last modified August 10 19:52 EDT 2020. Contains 336381 sequences. (Running on oeis4.)