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A107382
a(n) = 4*a(n-1)-4*a(n-3)-a(n-4).
0
4, 4, 16, 52, 188, 684, 2512, 9244, 34052, 125476, 462416, 1704212, 6280892, 23148428, 85314448, 314430012, 1158845444, 4270975556, 15740867728, 58013659124, 213811888828, 788013108844, 2904256931152, 10703766510172
OFFSET
0,1
FORMULA
G.f.: 4*(1-3*x+x^3)/(1-4*x+4*x^3+x^4) [Sep 28 2009]
MATHEMATICA
n = 4; b4 = x /. NSolve[x^4 - n*x^3 + n*x + 1 == 0, x][[4]] b3 = x /. NSolve[x^4 - n*x^3 + n*x + 1 == 0, x][[3]] b2 = x /. NSolve[x^4 - n*x^3 + n*x + 1 == 0, x][[2]] b1 = x /. NSolve[x^4 - n*x^3 + n*x + 1 == 0, x][[1]] digits = 25 a = Table[n*(b4^m + b3^m + b1^m + b2^m)/ (b4 + b3 + b2 + b1), {n, 0, digits}]
CROSSREFS
Sequence in context: A298448 A222144 A342817 * A257622 A185567 A203536
KEYWORD
nonn,easy
AUTHOR
Roger L. Bagula, May 24 2005
EXTENSIONS
Definition replaced by recurrence by the Associate Editors of the OEIS, Sep 28 2009
STATUS
approved