OFFSET
1,2
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..500
M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, arXiv:math/0205301 [math.CO], 2002. [pLink to arXiv version]
M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures]
FORMULA
E.g.f.: exp(exp(x/2)*(sqrt(5)*cosh(x*sqrt(5)/2)+sinh(x*sqrt(5)/2))/sqrt(5)-1)-1. - Vladimir Kruchinin, Feb 27 2015
MAPLE
f:= proc(n) option remember; `if`(n<2, 1, f(n-1) +f(n-2)) end: a:= proc(n) option remember; f(n) +add(binomial(n-1, k-1) *f(k) *a(n-k), k=1..n-1) end: seq(a(n), n=1..30); # Alois P. Heinz, Oct 07 2008
MATHEMATICA
f[n_] := f[n] = If[n<2, 1, f[n-1]+f[n-2]]; a[n_] := a[n] = f[n]+Sum [Binomial[n-1, k-1]*f[k]*a[n-k], {k, 1, n-1}]; Table[a[n], {n, 1, 30}] (* Jean-François Alcover, Mar 03 2014, after Alois P. Heinz *)
PROG
(PARI) Vec(serlaplace(exp( serconvol(Ser(1/(1-x-x^2)), exp(x))-1)))
/* ==> [1, 1, 3, 10, 42, 204, 1127, 6924, 46704, ...] (note offset 0) */
/* Joerg Arndt, Jun 16 2010 */
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved