A196836 (1^n + 2^n +3^n + 4^n)/2.

2, 5, 15, 50, 177, 650, 2445, 9350, 36177, 141170, 554325, 2186750, 8656377, 34355690, 136617405, 544061750, 2169039777, 8654570210, 34553579685, 138020346350, 551499730377, 2204254480730, 8811785649165, 35231447872550, 140878711512177, 563373614503250

Offset

0,1

Comments

2*a(n) = A001551(n), n>=0.

Links

Table of n, a(n) for n=0..25.

Formula

a(n) = (1^n + 2^n + 3^n + 4^n)/2, n>=0.

E.g.f.: (1-exp(4*x))/(2*(exp(-x)-1)) = sum(exp(j*x),j=1..4)/2.

O.g.f.: (2-5*x)*(1-5*x+5*x^2)/(product(1-j*x,j=1..4) (via Laplace transformation of the o.g.f.).

Mathematica

Table[Total[Range[4]^n]/2, {n, 0, 40}] (* T. D. Noe, Oct 10 2011 *)

Crossrefs

Cf. A001551/2.

Sequence in context: A149951 A367317 A157135 * A365247 A369212 A279553

Adjacent sequences: A196833 A196834 A196835 * A196837 A196838 A196839

Keyword

nonn,easy

Author

Wolfdieter Lang, Oct 10 2011

Status

approved