A173597 a(n) = a(n-1) + a(n-2) - [a(n-4)/4] - [a(n-5)/2] - [a(n-6)/4].

1, 1, 2, 3, 5, 8, 13, 20, 31, 47, 70, 104, 154, 227, 334, 489, 716, 1046, 1528, 2229, 3251, 4739, 6906, 10063, 14661, 21358, 31112, 45318, 66008, 96142, 140028, 203946, 297035, 432613, 630068, 917646, 1336476, 1946466, 2834861, 4128729, 6013131, 8757595, 12754659, 18576026, 27054324, 39402205, 57385786, 83577258, 121722786, 177278325, 258189982

Offset

0,3

Links

Table of n, a(n) for n=0..50.

Mathematica

f[-4] = 0; f[-3] = 0; f[-2] = 0; f[-1] = 0; f[0] = 1; f[1] = 1;
f[n_] := f[n] = f[n - 1] + f[n - 2] - Floor[f[n - 4]/4] - Floor[f[n - 5]/2] - Floor[f[n - 6]/4]
Table[f[n], {n, 0, 50}]
nxt[{a_, b_, c_, d_, e_, f_}]:={b, c, d, e, f, f+e-Floor[c/4]-Floor[b/2]-Floor[a/4]}; NestList[nxt, {1, 1, 2, 3, 5, 8}, 50][[;; , 1]] (* Harvey P. Dale, Mar 26 2025 *)

Crossrefs

Sequence in context: A156145 A216053 A361721 * A059923 A266331 A055805

Adjacent sequences: A173594 A173595 A173596 * A173598 A173599 A173600

Keyword

nonn,easy

Author

Roger L. Bagula, Nov 23 2010

Status

approved