Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #5 Mar 30 2012 18:37:44
%S 1,2,3,4,5,7,7,9,11,13,12,17,15,21,23,23,22,31,27,37,36,38,36,49,43,
%T 52,54,60,54,74,58,74,74,82,83,97,77,100,104,115,100,132,107,138,137,
%U 136,130,165,140,174,165,182,166,215,189,217,200,216,207,265,208,260,266
%N Row sums of triangle A117170 of Inverse-Shift-Moebius coefficients and so equals the Inverse-Shift-Moebius transform of [1,1,1,...].
%o (PARI) {a(n)=if(n<1,0,sum(k=1,n,prod(i=0,n, matrix(n,n,r,c,if(r>=c,if((r+i)%(c+i)==0,1,0))))[n,k]))}
%Y Cf. A117170 (triangle), A117171 (column 1), A117172 (column 2), A117173 (column 3).
%K nonn
%O 1,2
%A _Wouter Meeussen_ and _Paul D. Hanna_, Mar 05 2006