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A024428
S(n,n) + S(n-1,n-2) + S(n-2,n-4) + ... + S(n-k+1,n-2k+2), where k = [ (n+1)/2 ] and S(i,j) are Stirling numbers of second kind.
2
1, 1, 2, 4, 8, 18, 42, 102, 260, 684, 1860, 5216, 15020, 44388, 134336, 415672, 1313696, 4234904, 13911528, 46525992, 158279872, 547327904, 1922455440, 6854491840, 24794405328, 90940138256, 338037825952, 1272862982272, 4853075024192
OFFSET
1,3
FORMULA
G.f.: Sum_{k>=0} x^k / Product_{l=1..k} (1-l*x^2). - Ralf Stephan, Apr 18 2004
G.f.: 1/x/Q(0) - 1/x where Q(k)= 1 - x/(1 - x^2*(k+1)/Q(k+1)); (continued fraction). - Sergei N. Gladkovskii, Apr 14 2013
CROSSREFS
Sequence in context: A078678 A261492 A027056 * A330269 A049075 A318797
KEYWORD
nonn
EXTENSIONS
More terms from Sean A. Irvine, Jul 10 2019
STATUS
approved