23120

Appears in sequences

• Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 19.at n=7A031697
• Number of reversible strings with n-1 beads of 2 colors. 4 beads are black. String is not palindromic.at n=29A032091
• Sequence A014486 shown in base 4.at n=32A085185
• a(n) = T(n)^2 - n^2, where T(n) is a triangular number.at n=17A085740
• Products x*y*z arising from A102495.at n=35A102509
• Row sums of correlation triangle for (1+x)^3/(1-x).at n=39A115293
• a(n) = 64*n^2 + 16.at n=18A157912
• a(n) = 361*n^2 + 2*n.at n=7A158309
• a(n) = 20*n^2.at n=34A195322
• Numbers m such that the GCD of the x's that satisfy sigma(x) = m is 3.at n=39A241648
• Numbers n such that n!3 + 3^3 is prime.at n=36A247886
• Alternating sum of 10-gonal (or decagonal) pyramidal numbers.at n=32A269441
• E.g.f. A(x) satisfies: A( tanh( A(x) ) ) = tan(x).at n=4A279837
• E.g.f. A(x) satisfies: A( tan( A(x) ) ) = tanh(x).at n=4A279839
• Number of n-element subsets of [n+4] having an even sum.at n=30A282080
• Number of 3-cycles in the n X n rook graph.at n=16A288961
• Trajectory of 48 under the map x -> A289667(x).at n=9A290350
• Maximal coefficient of (1 - x) * (1 - x^4) * (1 - x^9) * ... * (1 - x^(n^2)).at n=51A369728
• Maximum of the absolute value of the coefficients of (1 - x) * (1 - x^4) * (1 - x^9) * ... * (1 - x^(n^2)).at n=51A369986
• a(n) = Sum_{k=0..floor(n/4)} binomial(n,k) * binomial(2*k,n-4*k).at n=17A389126