34720

Appears in sequences

• Number of partitions of n of the form a_1*b_1^2 + a_2*b_2^2 + ...; number of semisimple rings with p^n elements for any prime p.at n=34A004101
• Expansion of Product_{m>=1} (1 - m*q^m)^7.at n=15A022667
• Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 19 (most significant digit on right).at n=31A029512
• Convolution of L(n+1) := A000204(n+1) (Lucas), n>=0, with L(n+7), n>=0.at n=9A067985
• Numbers k such that k*Sum_{d|k} 1/sigma(d) is an integer.at n=23A069166
• a(n) = Sum_{k=1..2^n} d(k) where d(n) = number of divisors of n (A000005).at n=12A085831
• A triangular sequence from 2^n times the coefficients of characteristic polynomials of a rational tridiagonal matrix type: M(3)= {{1/2,-1,0} {-1,1/2,-m}, {0,-1,1/2}}};m=-1; polynomial recursion associated is: p(x, n) = (1 - 2*x)*p(x, n - 1)/2 - p(x, n - 2);.at n=59A136330
• Triangle T(n,k), n >= 0, 0 <= k <= n, read by rows: Number T(n,k) of forests of labeled rooted trees on n or fewer nodes using a subset of labels 1..n and k edges.at n=31A144289
• a(n+1)-+a(n)=prime, a(n+1)*a(n)=Average of twin prime pairs, a(1)=1,a(2)=4.at n=39A154493
• a(n) = 12*n^3 + 9*n^2 + 2*n.at n=14A191745
• Number of n-bead necklaces labeled with numbers -7..7 allowing reversal, with sum zero with no three beads in a row equal.at n=5A209343
• Number of 6-bead necklaces labeled with numbers -n..n allowing reversal, with sum zero with no three beads in a row equal.at n=6A209347
• Sigma(n) values in A115920.at n=35A216372
• Palindromic in bases 6 and 15.at n=23A249155
• Number of partitions of 5n into exactly 4 parts.at n=34A256327
• Expansion of Product_{k>=0} 1/(1-x^(4*k+3))^(4*k+3).at n=39A285131
• Number of 6-cycles in the n-halved cube graph.at n=4A290029
• Number of binary words of length n with three times as many occurrences of subword 101 as occurrences of subword 010.at n=19A307795
• a(n) = [x^(n^2)] Product_{k=1..n} (x^(k^2) + 1 + 1/x^(k^2)).at n=16A369434