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a(0) = a(1) = 1. a(n) = a(n-1) + a(n - b(n)), where b(n) is smallest prime dividing n.
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%I #11 Mar 08 2015 19:21:07

%S 1,1,2,3,5,6,11,12,23,34,57,58,115,116,231,346,577,578,1155,1156,2311,

%T 3466,5777,5778,11555,13866,25421,36976,62397,62398,124795,124796,

%U 249591,374386,623977,748772,1372749,1372750,2745499,4118248,6863747

%N a(0) = a(1) = 1. a(n) = a(n-1) + a(n - b(n)), where b(n) is smallest prime dividing n.

%H James A. Sellers, Feb 18 2008, <a href="/A137808/b137808.txt">Table of n, a(n) for n = 0..101</a>

%p 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

%t a = {1, 1}; Do[AppendTo[a, a[[ -1]] + a[[n - FactorInteger[n][[1, 1]] + 1]]], {n, 2, 70}]; a (* _Stefan Steinerberger_, Feb 14 2008 *)

%Y Cf. A137809, A020639.

%K nonn

%O 0,3

%A _Leroy Quet_, Feb 11 2008

%E Corrected and extended by _Stefan Steinerberger_, Feb 14 2008