27161

Appears in sequences

• Triangle read by rows: T(n,k) = number of noncommutative symmetric polynomials of degree n that have exactly k different variables appearing in each monomial and which generate the algebra of all noncommutative symmetric polynomials (n >= 1, 1 <= k <= n).at n=49A055105
• Triangle T(n,k) giving number of symmetric polynomials of degree n in k noncommuting variables, n >=2, 2 <= k <= n.at n=39A055106
• Triangle T(k,n) giving number of symmetric polynomials of degree n in k noncommuting variables, n >=2, 2 <= k <= n.at n=41A055107
• a(n) = prime(n)*prime(n+3).at n=36A090090
• Brilliant numbers (A078972) whose digit reversal is a pentagonal number (A000326).at n=10A115679
• Semiprimes (A001358) whose digit reversal is a pentagonal number (A000326).at n=34A115708
• a(n) = Sum_{k=0..n} (-1)^(n-k)*floor(sqrt(Bell(k))).at n=15A192572
• Sequence of pairwise relatively prime numbers of class P_6 (see comment in A275246).at n=19A275251