A283839 Row sums of A283838.

1, 3, 6, 12, 24, 42, 76, 136, 240, 424, 753, 1337, 2388, 4280, 7706, 13940, 25332, 46224, 84696, 155786, 287574, 532624, 989554, 1843744, 3444389, 6450369, 12107004, 22771642, 42913116, 81014528, 153199818, 290152952, 550332614, 1045234672, 1987731140

Offset: 8

Author

N. J. A. Sloane, Mar 25 2017

Keywords

• nonn

Comments

a(n) is odd for n >= 8 and n in { A247375 }. - Alois P. Heinz, Mar 26 2017

Links

• Alois P. Heinz, Table of n, a(n) for n = 8..1000
• Stefano Bilotta, Variable-length Non-overlapping Codes, arXiv preprint arXiv:1605.03785, 2016

Crossrefs

Cf. A247375, A283838.

Programs

Maple

b:= proc(n, l, c, k) option remember; `if`(n=0, l,
      b(n-1, 1-l, 1, k)+`if`(c=k-1, 0, b(n-1, l, c+1, k)))
    end:
a:= proc(n) option remember; `if`(n<8, 0, a(n-1)+
      add(b(n-2*k-1, 0, 1, k), k=3..floor(n/2)-1))
    end:
seq(a(n), n=8..60);  # Alois P. Heinz, Mar 26 2017

Mathematica

nMax = 60; gf[k_] := gf[k] = x^(2k)(x-x^k)^2 / ((1-x)(1-x^k)(1-2x+x^k)) + O[x]^(nMax+1); a[n_] := Sum[SeriesCoefficient[gf[k], n], {k, 3, Floor[ n/2] - 1}]; Table[a[n], {n, 8, nMax}] (* Jean-François Alcover, Apr 05 2017 *)

Extensions

More terms from Alois P. Heinz, Mar 26 2017