38640

Appears in sequences

• a(n) = Sum_{k=1..n-1} k*sigma(k)*sigma(n-k).at n=20A000441
• Denominators of Cauchy numbers of first type.at n=45A006233
• a(n) = n*(n + 1)*(3*n + 1).at n=23A027903
• Numbers whose base-14 representation has exactly 5 runs.at n=13A043666
• T(n,6), array T as in A050186; a count of aperiodic binary words.at n=14A050191
• a(n) = Sum_{d|4} phi(d)*n^(4/d).at n=14A054603
• a(n) = C(3+n, n) + C(4+n, n) + C(5+n, n) + C(6+n, n).at n=13A062966
• Integers k such that omega(k) = omega(k-1) + omega(k-2) + omega(k-3), where omega(n) is the number of distinct prime factors of n.at n=31A076252
• Numbers that can be expressed as the difference of the squares of primes in exactly six distinct ways.at n=22A092002
• Triangle read by rows: T(n,k) is number of noncrossing trees with n edges and having k nonroot branch nodes.at n=23A101431
• Records in A007374.at n=19A105207
• Triangle where T(n,k) = -n!*[x^k] ( x/log(1-x-x^2) )^(n+1), for n>=k>=0, read by rows.at n=23A118791
• Denominators of a-sequence for Sheffer matrix A130191 (Stirling2 squared).at n=45A130409
• a(n) = A008893(n)/2.at n=14A152041
• Number of permutations of {1,...,n} avoiding adjacent step pattern up, up, down, down, down.at n=8A177531
• Third accumulation array, T, of the natural number array A000027, by antidiagonals.at n=70A185508
• Riordan array (1, (A000045(x)/x-1) *A001006(A000045(x)/x-1) ).at n=37A187537
• Triangle of coefficients arising from an expansion of Integral( exp(exp(exp(x))), dx).at n=33A188881
• Numbers with prime factorization p*q*r*s*t^4 (where p, q, r, s, t are distinct primes).at n=5A190110
• Denominator of Sum_{k=1..n}(-1)^k/phi(k), where phi = A000010.at n=47A211178