19480

Appears in sequences

• Column 6 of triangle A091602.at n=44A091609
• Number of partitions of 2n free of multiples of 8 such that 4 occurs at most once. All odd parts occur with even multiplicities. There is no restriction on the other even parts.at n=27A100684
• Number of admirable numbers < 10^n.at n=5A109727
• Number of ways to place n nonattacking empresses on an n X n board.at n=8A137774
• a(n) is the smallest integer k such that the n-th (backward) difference of the partition sequence A000041 is positive from k onwards.at n=33A155861
• Cardinality of the Weyl alternation set corresponding to the zero-weight in the adjoint representation of the Lie algebra sp(2n).at n=14A232165
• Maximum value of the cyclic convolution of the first n positive integers with themselves.at n=39A294172
• Harary index of the n X n queen graph.at n=15A296196
• G.f.: Sum_{k>=0} q(k)^2 * x^k / Sum_{k>=0} q(k)*x^k, where q(n) is A000009(n).at n=35A304877
• G.f. A(x) satisfies: 1 = A(x) - x/(A(x) - 3^2*x/(A(x) - 5^2*x/(A(x) - 7^2*x/(A(x) - 9^2*x/(A(x) - ...))))), a continued fraction relation.at n=4A338636
• a(n) = Sum_{k=1..floor(n/2)} k * (n-k) * floor((n-k)/k).at n=42A339804
• Numbers k such that prime(k) is the hypotenuse of a Pythagorean triple where one leg is also prime.at n=25A342583