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%I #7 Feb 17 2021 20:29:37
%S 1,1,1,1,2,2,4,4,6,7,11,11,17,17,25,29,38,38,54,54,72,80,102,102,136,
%T 140,174,186,228,228,300,300,366,388,464,480,594,594,702,736,874,874,
%U 1068,1068,1250,1324,1528,1528,1828,1844,2144,2220,2534,2534,2982,3026,3464,3572,4028,4028
%N a(1) = a(2) = 1; a(n+1) = Sum_{d|n, d < n} a(n/d) * a(d).
%t a[1] = a[2] = 1; a[n_] := a[n] = Sum[If[d < (n - 1), a[(n - 1)/d] a[d], 0], {d, Divisors[n - 1]}]; Table[a[n], {n, 60}]
%o (PARI) A341697(n) = if(n<3, 1, sumdiv(n-1,d,if(d<(n-1), A341697((n-1)/d)*A341697(d), 0))); \\ _Antti Karttunen_, Feb 17 2021
%Y Cf. A038044, A122698, A333051, A341698.
%K nonn
%O 1,5
%A _Ilya Gutkovskiy_, Feb 17 2021
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