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A084775 a(n) = sum of absolute valued coefficients of (1+1*x-4*x^2)^n. 2
1, 6, 34, 184, 956, 4776, 22986, 118304, 624634, 3281346, 17687330, 92606914, 470392898, 2348031430, 11932314170, 62345998488, 326780375778, 1691296908076, 8780141027670, 45168987187058, 230213109996786 (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+1*x-4*x^2)^n, k, x))); print1(S", "))

CROSSREFS

Sequence in context: A144142 A126643 A320745 * A327740 A229009 A085351

Adjacent sequences:  A084772 A084773 A084774 * A084776 A084777 A084778

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jun 14 2003

STATUS

approved

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Last modified October 30 12:22 EDT 2020. Contains 338079 sequences. (Running on oeis4.)