33661

Appears in sequences

• a(n) = (n+1)*(n^2+n+2)/2; g.f.: (1 + 2*x^2) / (1 - x)^4.at n=40A006000
• Strong pseudoprimes to base 51.at n=22A020277
• a(n) = Sum_{k=1..n} lcm(n,k).at n=40A051193
• Number of 3 X 3 X 3 magic cubes with sum 3n.at n=10A070302
• Least number k > 1 (that is not the power of prime p) such that k divides (p+1)^k-1, where p = prime(n).at n=12A128356
• Least number k > n such that k^2 divides n^k - 1.at n=39A128452
• E.g.f.: (1+sqrt(2)*sin(x/sqrt(2))*cosh(x/sqrt(2))+sin(x/sqrt(2))*sinh(x/sqrt(2)))/(cos(x/sqrt(2))*cosh(x/sqrt(2))).at n=12A178964
• Generalized Euler numbers. Square array A(n,k), n >= 1, k >= 0, read by antidiagonals. A(n,k) = n-alternating permutations of length n*k.at n=24A181985
• 4-alternating permutations of length 4n.at n=3A211212
• n-alternating permutations of length 3n.at n=3A211213
• Number of partitions of n such that m(2) = m(3), where m = multiplicity.at n=49A240064
• Table read by rows: each row represents the constant and exponent of a Colbert number.at n=2A258074
• Unsigned numerators of the nonzero coefficients in the expansion of 1/hypergeom([], [Seq_{k=1..m-1} k/m], (x/m)^m) for m = 4.at n=3A273192
• Triangle read by rows, coefficients of generalized Eulerian polynomials F_{4;n}(x).at n=6A292606
• Positive integers m with m^k - 1 (k = 1,...,13) all practical.at n=27A294307
• The fifth term of the greedy B_n set of natural numbers.at n=39A369817