%I #22 May 03 2020 18:52:06
%S 1,1,1,2,3,4,5,6,8,9,10,11,13,16,20,25,31,32,33,34,36,39,43,48,54,62,
%T 71,81,92,105,121,141,166,167,168,169,171,174,178,183,189,197,206,216,
%U 227,240,256,276,301
%N a(n) = a(n-1) + a(m) for n >= 4, where m = n - 1 - 2^p and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = a(3) = 1.
%H Ivan Neretin, <a href="/A050026/b050026.txt">Table of n, a(n) for n = 1..8193</a>
%t Fold[Append[#1, #1[[-1]] + #1[[#2]]] &, {1, 1, 1}, Flatten@Table[k, {n, 5}, {k, 2^n}]] (* _Ivan Neretin_, Aug 30 2015 *)
%o (PARI) lista(nn) = {nn = max(nn,3); my(va = vector(nn)); va[1] = 1; va[2] = 1; va[3] = 1; for(n=4, nn, va[n] = va[n-1] + va[n - 1 - 2^logint(n-2, 2)]); va;} \\ _Petros Hadjicostas_, May 03 2020
%K nonn
%O 1,4
%A _Clark Kimberling_
%E Name edited by _Petros Hadjicostas_, Apr 25 2020