A046949 - OEIS

%I #20 Jan 14 2024 07:58:03

%S 1,25,49,145,169,313,409,601,625,937,1081,1369,1465,1801,1993,2569,

%T 2593,3025,3337,3817,3961,4729,5017,5593,5689,6433,6769,7729,7921,

%U 8641,9217,9985,10009,11161,11593,12745,13057,13969,14449,15793

%N Sizes of successive balls in D_4 lattice.

%C The subsequence of primes in this partial sum begins: 313, 409, 601, 937, 1801, 1993, 2593, 4729, 5689, 8641, 10009, 11161, 11593, 14449. [_Jonathan Vos Post_, Feb 18 2010]

%H Seiichi Manyama, <a href="/A046949/b046949.txt">Table of n, a(n) for n = 0..10000</a>

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

%F a(n) ~ Pi^2 * n^2. - _Vaclav Kotesovec_, Jan 14 2024

%t A004011 = Join[{1}, Table[24*Sum[d*Mod[d, 2], {d, Divisors[n]}], {n, 1, 40}]]; Accumulate[A004011](* _Jean-François Alcover_, Apr 25 2012 *)

%o (PARI) B=1; bl=[ 1 ]; for (n=1,200,t1=divisors(2*n); t2=0; for (i=1, length(t1), if( t1[ i ]%4 <> 0, t2=t2+t1[ i ])); B=B+8*t2; bl=concat(bl,B)); bl

%Y Partial sums of A004011.

%K nonn

%O 0,2

%A _N. J. A. Sloane_