A261058 Column k=1 of A213221.

1, 3, 10, 32, 106, 357, 1222, 4230, 14770, 51918, 183472, 651191, 2319626, 8288135, 29691760, 106611596, 383565754, 1382423748, 4990274016, 18039252192, 65292492328, 236595647526, 858231115540, 3116138603103, 11324267454946, 41186435585589, 149907159998452, 545997804435897

Offset

1,2

Links

Table of n, a(n) for n=1..28.

Donatella Merlini, Massimo Nocentini, Algebraic Generating Functions for Languages Avoiding Riordan Patterns, Journal of Integer Sequences, Vol. 21 (2018), Article 18.1.3.

Formula

Conjecture: n*a(n) +(n-3)*a(n-1) +3*(-7*n+10)*a(n-2) +3*(n-1)*a(n-3) +40*(n-2)*a(n-4) +2*(-2*n+3)*a(n-5) +10*(-2*n+5)*a(n-6)=0.

Crossrefs

Cf. A213221.

Sequence in context: A297067 A063782 A071718 * A306295 A356499 A134952

Adjacent sequences: A261055 A261056 A261057 * A261059 A261060 A261061

Keyword

nonn

Author

R. J. Mathar, Aug 08 2015

Status

approved