68040

Appears in sequences

• Number of labeled Abelian groups of order n.at n=8A034382
• Number of labeled groups.at n=8A034383
• Number of strings of n distinct digits from 0-9 that are the last n digits of a square in base 9.at n=6A036753
• There are exactly n integer-sided triangles of area a(n).at n=36A051586
• a(n) = (3*n+9)!!!/9!!!, related to A032031 ((3*n)!!! triple factorials).at n=4A051609
• Triangle read by rows: T(n,k) is the number of labeled commutative monoids of order n with k idempotents.at n=36A058159
• a(n) = n^n * (n^2 - 1)/24.at n=3A060348
• Numbers k such that k^6 + 1091 is prime.at n=35A066386
• Square of lower triangular matrix of A056857 (successive equalities in set partitions of n).at n=38A078937
• Partial sums of n 3-spaced triangular numbers beginning with t(3), e.g., a(2) = t(3)+t(6) = 6+21 = 27.at n=34A085788
• a(1) = 1. For n > 1, a(n) = a(n-1) if n is prime, a(n) = a(n-1)/n if n is composite and divides a(n-1) else a(n) = n*a(n-1).at n=19A088304
• Numbers n divisible by exactly three nontrivial permutations (rearrangements) of the digits of n.at n=9A090058
• Row 9 of array in A288580.at n=21A092974
• Smallest k > 1 such that (sum of digits of k^n)*(sum of digits of k^(n+1)) = k, or 0 if no such k exists.at n=13A126783
• Third column of PE^2.at n=8A129324
• Number of permutations of n elements divided by the number of (binary) heaps on n+1 elements.at n=17A133385
• Triangle: p(x) = (t/log(1 + t))^a0*(1 + t)^x; a0=2; weights (n+1)!*n!.at n=22A137381
• A vector sequence with set row sum function: row(n)=(n+1)! and linear build up and decline function: f(n,m)=Floor[(m/n)*row(n)].at n=39A152970
• A vector sequence with set row sum function: row(n)=(n+1)! and linear build up and decline function: f(n,m)=Floor[(m/n)*row(n)].at n=41A152970
• Triangle related to the asymptotic expansion of E(x,m=3,n).at n=32A163932