895068996640domain: NAppears in sequencesBinomial coefficient C(5n+10,n).at n=11A004344Binomial coefficients C(n,54).at n=11A017718Binomial coefficients C(65,n).at n=11A017781a(n) = [x^n] 1/(1 - x)^(n*(n-1)/2).at n=11A386879