42449

Appears in sequences

• 9-gonal (or enneagonal) pyramidal numbers: a(n) = n*(n+1)*(7*n-4)/6.at n=33A007584
• a(i)=a(i-1)+a(j_1)*a(j_2) {where j_1+j_2=i-1, j_1 <= q j_2} + a(j_1)*a(j_2)*a(j_3) {where j_1+j_2+j_3=i-1, j_1 <= q j_2 <= q j_3} +...+ a(1)^{i-1}.at n=13A027881
• Expansion of 1/(1 - x - x^2 + x^3 - x^7 + x^9 - x^11).at n=39A147663
• a(n) = n*(2*n^2 + 5*n + 15)/2.at n=34A163673
• Odd 9-gonal (nonagonal) pyramidal numbers.at n=8A218328
• O.g.f.: Sum_{n>=0} n! * x^n * Product_{k=1..n} (k + x) / (1 + k^2*x + k*x^2).at n=6A221370
• Least k > a(n-1) such that k^3 has no digit in common with a(n-1) and a(n+1), a(0)=0.at n=29A294662
• (Number of 4 X 4 pandiagonal magic squares with distinct positive entries less than n)/384.at n=35A317252
• a(n) = (9*n/4 - 51/8 - 5/(16*n-24) + 1/n + 6/(n+1))*binomial(2*n-2,n-1).at n=5A344728