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A137160
G.f.: 1 = Sum_{n>=0} a(n)*x^n*(1-x)/(1+x)^(2^n).
4
1, 2, 4, 12, 64, 664, 13856, 584668, 49751520, 8509625760, 2919099754336, 2005648412219832, 2758163973596156000, 7588978611071894509464, 41769719229784446295570112, 459846172005153447271276789620
OFFSET
0,2
COMMENTS
Equals the unsigned row sums of triangle A137156.
PROG
(PARI) {a(n)=polcoeff(1-sum(k=0, n-1, a(k)*x^k*(1-x)/(1+x+x*O(x^n))^(2^k) ), n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jan 24 2008
STATUS
approved