login
A132785
Main diagonal of triangle A132784.
2
1, 1, 1, 1, 2, 7, 40, 342, 4118, 66581, 1393998, 36722251, 1189340060, 46466456210, 2155486553918, 117137645018204, 7372271485024724, 532031521606758006, 43644205623323138712, 4038679603699275061593, 418716209086799704826908
OFFSET
0,5
COMMENTS
Also equals (with offset) the row sums and rightmost border of triangle A132784.
PROG
(PARI) {a(n)=local(A=[1]); if(n==0, 1, for(i=1, n, B=Vec(Pol(A)/(1-x +x*O(x^(i*(i-1)/2)))); A=concat(vector(i), B)); A[n+1])}
CROSSREFS
Cf. A132784 (triangle), A132786 (column sums).
Sequence in context: A031973 A274279 A319945 * A224677 A064626 A137731
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 29 2007
STATUS
approved