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A084779 a(n) = sum of absolute-valued coefficients of (1+2x-4x^2)^n. 2
1, 7, 41, 207, 1313, 7807, 42593, 232463, 1290433, 7604415, 42034721, 236031231, 1363681121, 7457831007, 39670144513, 231087069823, 1291433872385, 7373001299199, 41437235793921, 229538650588863, 1268719471103233 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..20.

PROG

(PARI) for(n=0, 40, S=sum(k=0, 2*n, abs(polcoeff((1+2*x-4*x^2)^n, k, x))); print1(S", "))

CROSSREFS

Sequence in context: A237854 A219862 A238991 * A266887 A237664 A168584

Adjacent sequences:  A084776 A084777 A084778 * A084780 A084781 A084782

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jun 14 2003

STATUS

approved

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Last modified July 12 18:03 EDT 2020. Contains 335666 sequences. (Running on oeis4.)