40986

Appears in sequences

• Numbers k such that k | sigma_3(k) - phi(k)^3.at n=23A055697
• a(n) = n*(n+1)*(n^2 + 2)/6.at n=22A071239
• Number of permutations of length n which avoid the patterns 1324, 2431, 4123.at n=10A116830
• A transform of the central binomial coefficients C(n,floor(n/2)).at n=14A119967
• Number of ways to tile an n X 1 strip with 1 X 1 squares and 2 X 1 dominoes with the restriction that no three consecutive tiles are of the same type.at n=33A137200
• a(n) = 100*n^2 - 151*n + 57.at n=20A157626
• Nonnegative walks of length n on the x-axis starting at the origin using steps {1,-1} and visiting no point more than twice.at n=32A212584
• Integers that are Rhonda numbers to base 30.at n=23A255736
• 25-gonal pyramidal numbers: a(n) = n*(n+1)*(23*n-20)/6.at n=22A256645
• Number of ways to write n as an ordered sum of nine powers of 2.at n=35A342252
• Number of ways to place a non-attacking black king and white king on an n X n board, up to rotation and reflection.at n=24A357723
• a(n) = n! * (1 + Sum_{k=0..n} (-1)^k * binomial(k+3,4) / k!).at n=8A368768