A005880 - OEIS

%I M1827 #26 Dec 01 2017 03:02:02

%S 2,8,12,16,26,24,28,48,36,40,64,48,62,80,60,64,96,96,76,112,84,88,156,

%T 96,114,144,108,144,160,120,124,208,168,136,192,144,148,248,192,160,

%U 242,168,216,240

%N Theta series of D_4 lattice with respect to edge.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H G. C. Greubel, <a href="/A005880/b005880.txt">Table of n, a(n) for n = 0..5000</a>

%H <a href="/index/Da#D4">Index entries for sequences related to D_4 lattice</a>

%t Table[2 DivisorSigma[1, 2 n + 1], {n, 0, 43}] (* _Jean-François Alcover_, Jul 06 2017 *)

%o (PARI) for(n=0, 30, print1(2*sigma(2*n+1), ", ")) \\ _G. C. Greubel_, Nov 30 2017

%Y Equals 2 * A008438.

%K nonn

%O 0,1

%A _N. J. A. Sloane_