24465

Appears in sequences

• Expansion of e.g.f. exp(-x^2/2) / (1-x).at n=8A000266
• Bruckman-Lucas pseudoprimes: k | (L_k - 1), where k is composite and L_k = Lucas numbers A000032.at n=10A005845
• Second-order Fibonacci numbers.at n=19A010049
• a(n) = Sum_{k>=1} floor(tau^(n-k)) where tau is A001622.at n=19A020956
• Every suffix prime and no 0 digits in base 9 (written in base 9).at n=46A024784
• T(n,1) + T(n,2) + ... T(n,n), where T is the array in A026098.at n=32A026101
• a(n) = self-convolution of row n of array T given by A027926.at n=9A027989
• Triangle T(n,k), 0<=k<=n, read by rows, defined by: T(n,k)=0 if k>n, T(n,0) = A000108(n); T(n+1,k)= Sum_{j=0..n} T(n-j,k-1)*binomial(2j+1,j+1).at n=49A090285
• Triangle T(n,k) = number of permutations of n elements with k 2-cycles.at n=20A114320
• Triangle T(n,k), the number of permutations on n elements that have no cycles of length k.at n=29A122974
• Convolution of Lucas numbers and positive integers repeated (A000032 and A008619).at n=18A213046
• G.f.: Sum_{n>=0} x^n * Sum_{k=0..n} binomial(n,k)^2 * x^k/(1-2*x)^k.at n=10A217664
• a(n) is the number m such that f(sqrt(n)) is in the field Q(sqrt(m)), where f(x) is defined from the continued fraction x = [c(0), c(1), ... ] as [1/c(0), 1/c(1), ...].at n=18A229956
• Nonequivalent ways to place two different markers (e.g., a pair of Go stones, black and white) on an n X n grid.at n=20A242709
• a(n) gives the odd leg of one of the two Pythagorean triangles with hypotenuse A080109(n) = A002144(n)^2. This is the smaller of the two possible odd legs.at n=22A253802
• Odd composite integers m such that A014448(m) == 4 (mod m).at n=40A335670
• Expansion of e.g.f. -LambertW(-3*x / (1 + x))/3.at n=5A376105
• Antidiagonal sums of A382310.at n=42A382311