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A055873 a(0) = 1; a(n) = sum_{k=1 to d(n)} [a(n-k)] where d(n) is number of positive divisors of n. 1
1, 1, 2, 3, 6, 9, 20, 29, 64, 113, 226, 339, 791, 1130, 2486, 4746, 9492, 14238, 32883, 47121, 110966, 205208, 396178, 601386, 1417472, 2415036, 4830072, 9263966, 18924110, 28188076, 66036296, 94224372, 221466892, 409915636, 791643196 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000

EXAMPLE

Since d(8) = 4, a(8) = a(7) +a(6) +a(5) +a(4) {4 terms}. So a(8) = 29 +20 +9 +6 =64.

MATHEMATICA

Module[{lst={1}, n=1}, Do[AppendTo[lst, Total[Take[lst, -DivisorSigma[0, n]]]]; n++, {40}]; lst] (* Harvey P. Dale, May 01 2012 *)

CROSSREFS

Sequence in context: A319755 A003243 A320160 * A246565 A320169 A293606

Adjacent sequences:  A055870 A055871 A055872 * A055874 A055875 A055876

KEYWORD

easy,nonn

AUTHOR

Leroy Quet, Jul 16 2000

STATUS

approved

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Last modified February 23 13:14 EST 2020. Contains 332159 sequences. (Running on oeis4.)