A108105 2^floor(n/5).

1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 4, 4, 4, 4, 4, 8, 8, 8, 8, 8, 16, 16, 16, 16, 16, 32, 32, 32, 32, 32, 64, 64, 64, 64, 64, 128, 128, 128, 128, 128, 256, 256, 256, 256, 256, 512, 512, 512, 512, 512, 1024

Offset: 0

Author

Roger L. Bagula, Jun 03 2005

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,2).

Programs

Mathematica

s[1] = {2}; s[2] = {3}; s[3] = {4}; s[4] = {5}; s[5] = {1, 6}; s[6] = {2}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] a0 = Table[Length[p[i]], {i, 0, 50}]

PARI

a(n)=2^(n\5) \\ Charles R Greathouse IV, Oct 03 2016

Formula

G.f.: (1+x+x^2+x^3+x^4)/(1-2*x^5).