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A193475
a(n) = 4*16^n - 2*4^n.
6
2, 56, 992, 16256, 261632, 4192256, 67100672, 1073709056, 17179738112, 274877382656, 4398044413952, 70368735789056, 1125899873288192, 18014398375264256, 288230375614840832, 4611686016279904256, 73786976286248271872, 1180591620683051565056
OFFSET
0,1
FORMULA
Recurrence: a(0) = 2, a(1) = 56, a(n) = 20*a(n-1) - 64*a(n-2).
G.f.: (16*x+2)/(64*x^2-20*x+1).
E.g.f.: 4*exp(16*x) - 2*exp(4*x).
MAPLE
A193475 := proc(n) 2^(2*n+1); %^2; % - %% end: seq (A193475(n), n=0..20);
CROSSREFS
Sequence in context: A080268 A224297 A193476 * A246001 A009555 A054959
KEYWORD
nonn
AUTHOR
Peter Luschny, Aug 07 2011
STATUS
approved