A173674 a(n) = ceiling(A003269(n)/2).

0, 1, 1, 1, 1, 1, 2, 2, 3, 4, 5, 7, 10, 13, 18, 25, 35, 48, 66, 91, 125, 173, 238, 329, 454, 626, 864, 1193, 1646, 2272, 3136, 4329, 5975, 8247, 11383, 15711, 21686, 29932, 41315, 57026, 78711, 108643, 149958, 206983, 285694, 394337, 544295, 751278, 1036972

Offset: 0

Author

Roger L. Bagula, Nov 25 2010

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, -1).

Crossrefs

Cf. A003269.

Programs

Mathematica

b[0] = 0; b[1] = 1; b[2] = 1; b[3] = 1;
b[n_] := b[n] = b[n - 1] + b[n - 4]
Table[b[n] - Floor[b[n]/2], {n, 0, 30}]

Formula

a(n) = A003269(n) - floor(A003269(n)/2):

a(n) = ceiling(A003269(n)/2).

a(n)= a(n-1) + a(n-4) + a(n-15) - a(n-16) - a(n-19). - R. J. Mathar, Sep 10 2016