21828

Appears in sequences

• The dimension of the space of invariant tensors in the n-th tensor power of the adjoint representation of the exceptional Lie algebra E7.at n=9A179683
• Numbers m with C(2*m, m) + prime(m) prime, where C(2*m, m) = (2*m)!/(m!)^2.at n=49A236242
• Numbers k such that 7*10^k - 23 is prime.at n=26A272271
• Solution of the complementary equation a(n) = 2*a(n-1) - a(n-2) + b(n-1) + n, where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=38A294872
• G.f. = Phi^3*F^3, where Phi = g.f. for A028930, F = g.f. for A028959.at n=14A328534
• Numbers k such that k and k+1 are both hoax numbers (A019506).at n=34A329935
• Expansion of e.g.f. exp( Sum_{k>=0} x^(3*k+4) / (3*k+4)! ).at n=17A365894