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A137808 a(0) = a(1) = 1. a(n) = a(n-1) + a(n - b(n)), where b(n) is smallest prime dividing n. 2
1, 1, 2, 3, 5, 6, 11, 12, 23, 34, 57, 58, 115, 116, 231, 346, 577, 578, 1155, 1156, 2311, 3466, 5777, 5778, 11555, 13866, 25421, 36976, 62397, 62398, 124795, 124796, 249591, 374386, 623977, 748772, 1372749, 1372750, 2745499, 4118248, 6863747 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

James A. Sellers, Feb 18 2008, Table of n, a(n) for n = 0..101

MAPLE

with(numtheory): a:=proc(n) option remember: if n = 0 or n = 1 then RETURN(1) fi: a(n-1) + a(n-ifactors(n)[2][1][1]): end: for i from 0 to 100 do printf(`%d, `, a(i)) od: # James A. Sellers, Feb 18 2008

MATHEMATICA

a = {1, 1}; Do[AppendTo[a, a[[ -1]] + a[[n - FactorInteger[n][[1, 1]] + 1]]], {n, 2, 70}]; a (* Stefan Steinerberger, Feb 14 2008 *)

CROSSREFS

Cf. A137809, A020639.

Sequence in context: A117086 A344551 A081026 * A275525 A091909 A171040

Adjacent sequences:  A137805 A137806 A137807 * A137809 A137810 A137811

KEYWORD

nonn

AUTHOR

Leroy Quet, Feb 11 2008

EXTENSIONS

Corrected and extended by Stefan Steinerberger, Feb 14 2008

STATUS

approved

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Last modified August 3 22:03 EDT 2021. Contains 346441 sequences. (Running on oeis4.)