A090411 G.f.: (1-x)/(1-16x).

1, 15, 240, 3840, 61440, 983040, 15728640, 251658240, 4026531840, 64424509440, 1030792151040, 16492674416640, 263882790666240, 4222124650659840, 67553994410557440, 1080863910568919040, 17293822569102704640, 276701161105643274240, 4427218577690292387840

Offset

0,2

Links

Table of n, a(n) for n=0..18.

Index entries for linear recurrences with constant coefficients, signature (16).

Formula

a(n) = 15*16^(n-1)+0^n/16.

a(n) = sum{j=0..3, sum{k=0..n, C(4n+j, 4k) }}.

a(n) = (A070775(n) + A090407(n) + A001025(n) + A090408(n))/4.

Mathematica

Join[{1, a = 15}, Table[a=16*a, {n, 0, 30}]] (* Vladimir Joseph Stephan Orlovsky, Jun 10 2011 *)
Join[{1}, NestList[16#&, 15, 20]] (* Harvey P. Dale, Dec 28 2016 *)

Prog

(PARI) a(n)=if(n, 15<<(4*n-4), 1) \\ Charles R Greathouse IV, Jun 10 2011

Crossrefs

Cf. A090409.

Sequence in context: A097262 A158557 A220821 * A154806 A133199 A059760

Adjacent sequences: A090408 A090409 A090410 * A090412 A090413 A090414

Keyword

easy,nonn

Author

Paul Barry, Nov 30 2003

Status

approved