50521

Appears in sequences

• Euler or up/down numbers: e.g.f. sec(x) + tan(x). Also for n >= 2, half the number of alternating permutations on n letters (A001250).at n=10A000111
• Euler (or secant or "Zig") numbers: e.g.f. (even powers only) sec(x) = 1/cos(x).at n=5A000364
• Triangle of Euler-Bernoulli or Entringer numbers read by rows: T(n,k) is the number of down-up permutations of n+1 starting with k+1.at n=53A008282
• Triangle of Euler-Bernoulli or Entringer numbers read by rows: T(n,k) is the number of down-up permutations of n+1 starting with k+1.at n=54A008282
• Read across rows of Euler-Bernoulli or Entringer triangle.at n=36A008283
• Triangle of coefficients in expansion of D^n (sec x) / sec x in powers of tan x.at n=30A008294
• Triangle of coefficients in expansion of D^n (sec x) / sec x in powers of tan x.at n=25A008294
• Triangle T(n,k) = P(n,k)/2, n >= 2, 1 <= k < n, of one-half of number of permutations of 1..n such that the differences have k runs with the same signs.at n=44A008970
• Triangle read by rows: T(n,k) is the number of permutations of [n] with k increasing runs of length at least 2.at n=35A008971
• Triangle read by rows: T(n,k) is the number of permutations of [n] with k increasing runs of length at least 2.at n=29A008971
• Expansion of (1+x)/cos(x).at n=10A009002
• Triangle of Euler-Bernoulli or Entringer numbers.at n=45A010094
• Triangle of Euler-Bernoulli or Entringer numbers.at n=46A010094
• Average theta series of odd unimodular lattices of dimension 22 (multiplied by 50521).at n=0A029823
• Numerators of Taylor series for sec(x) = 1/cos(x).at n=5A046976
• Numerator of S(n)/Pi^n, where S(n) = Sum_{k=-inf..+inf} (4k+1)^(-n).at n=10A050970
• Triangle of numbers related to A000330 (sum of squares) and A000364 (Euler numbers).at n=19A060058
• Triangle of numbers related to A000330 (sum of squares) and A000364 (Euler numbers).at n=20A060058
• Fifth column of triangle A060058.at n=1A060062
• Triangle of coefficients of certain polynomials used for G.f.s of columns of triangle A060058.at n=15A060063