24568

Appears in sequences

• Second-order Euler numbers.at n=7A002435
• Triangle of coefficients in expansion of D^n (sec x) / sec x in powers of tan x.at n=21A008294
• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 21 ones.at n=14A031789
• Numerators of continued fraction convergents to sqrt(818).at n=8A042578
• (2n+1)-digit anti-palindromic numbers or numberdromes, whose first and last digits add to ten, second and next-to-last add to ten and so on with the central digit a 5.at n=21A093472
• Triangle T(n,k), 0 <= k <= n, read by rows, defined by T(0,0) = 1; T(0,k) = 0 if k>0 or if k<0; T(n,k) = k*T(n-1,k-1) + (k+1)*T(n-1,k+1).at n=38A104035
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 0), (1, -1, 0), (1, 0, -1), (1, 1, 0)}.at n=9A149179
• Triangle read by rows: T(n,k) = value of (d^2n/dx^2n) (tan^(2k)(x)/cos(x)) at the point x = 0.at n=11A151775
• a(n) = 2*n*(9*n-1).at n=36A178574
• a(n) = 3*a(n-1) - 2*a(n-2) with a(0)=16 and a(1)=40.at n=10A182461
• Number of arrays of 4 integers in -n..n with sum zero and adjacent elements differing in absolute value.at n=16A202964
• E.g.f.: sec(x)^2*tan(x)+sec(x)*tan(x)^2.at n=8A225689
• Number of n X 3 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 4 binary array having two adjacent 1's and two adjacent 0's.at n=4A227439
• Number of n X 5 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 6 binary array having two adjacent 1's and two adjacent 0's.at n=2A227441
• T(n,k) = Number of n X k 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X (k+1) binary array having two adjacent 1's and two adjacent 0's.at n=23A227442
• T(n,k) = Number of n X k 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X (k+1) binary array having two adjacent 1's and two adjacent 0's.at n=25A227442
• a(n) = largest number of distinct words arising in Post's tag system {00, 1101} applied to a binary word w, over all starting words w of length n, or a(n) = -1 if there is a word w with an unbounded trajectory.at n=28A284116
• a(n) = largest number of distinct words arising in Post's tag system {00, 1101} applied to a binary word w, over all starting words w of length n, or a(n) = -1 if there is a word w with an unbounded trajectory.at n=30A284116
• a(n) = largest number of distinct words arising in Post's tag system {00, 1101} applied to a binary word w, over all starting words w of length n, or a(n) = -1 if there is a word w with an unbounded trajectory.at n=32A284116
• a(1) = 102735, a(n) = prime(n-1)*a(n-1) but products that are not in A010784 are first reduced as in A320486 (see comments); continue until zero is reached.at n=23A321149