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A343265 a(n) is the number of ways n can be reached starting from 0 and using only two operations: adding one or, once n > 1, squaring. 0

%I #23 May 07 2021 09:19:50

%S 1,1,1,1,2,2,2,2,2,3,3,3,3,3,3,3,5,5,5,5,5,5,5,5,5,7,7,7,7,7,7,7,7,7,

%T 7,7,9,9,9,9,9,9,9,9,9,9,9,9,9,11,11,11,11,11,11,11,11,11,11,11,11,11,

%U 11,11,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13

%N a(n) is the number of ways n can be reached starting from 0 and using only two operations: adding one or, once n > 1, squaring.

%F a(n) = a(n-1) + a(sqrt(n)) if n is a square or a(n-1) otherwise.

%t a[0]:=1; a[n_]:=If[IntegerQ[Sqrt[n]],a[n-1]+a[Sqrt[n]],a[n-1]]; Table[a[n],{n,0,80}] (* _Stefano Spezia_, May 06 2021 *)

%Y Cf. A097046.

%K nonn

%O 0,5

%A _James P. B. Hall_, Apr 09 2021

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Last modified May 26 05:37 EDT 2024. Contains 372807 sequences. (Running on oeis4.)