A156838 - OEIS

%I #4 Mar 03 2013 13:19:10

%S 1,3,3,7,3,13,3,17,11,17,3,51,3,21,37,55,3,83,3,113,63,29,3,271,75,33,

%T 103,223,3,453,3,329,139,41,427,897,3,45,189,1265,3,1267,3,651,1277,

%U 53,3,2943,929,1571,313,1001,3,3147,2009,4843

%N Row sums of triangle A156837

%C a(n) = 3 iff n is prime.

%F Row sums of triangle A156837.

%e a(4) = 7 since row 4 of triangle A156837 = (3, 3, 0, 1).

%p A156838 := proc(n)

%p     add(A156837(n,k),k=1..n) ;

%p end proc: # _R. J. Mathar_, Mar 03 2013

%Y A156837

%K nonn,easy

%O 1,2

%A _Gary W. Adamson_ & _Mats Granvik_, Feb 16 2009

%E Extended beyond a(14) by _R. J. Mathar_, Mar 03 2013