27949

Appears in sequences

• Expansion of e.g.f. exp(-x)/(1-2*x).at n=6A000354
• Number of rooted trees with n nodes with every leaf at height 7.at n=20A048812
• Numbers m such that the positive values of m - A002110(k) are all primes (k > 0).at n=44A068372
• Square array T(n,k) (row n, column k) read by antidiagonals defined by: T(n,k) is the permanent of the n X n matrix with 1 on the diagonal and k elsewhere; T(0,k)=1.at n=42A090628
• Number of interior balls in a truncated tetrahedral arrangement.at n=19A092966
• Structured octagonal anti-diamond numbers (vertex structure 7).at n=18A100187
• Numerators of convergents to 1 + 2/(3 + 4/(5 + 6/(7 + ...))).at n=5A113012
• Form the difference table of the sequence {2^k*k!}, then divide k-th column entries by 2^k*k!. Array read by ascending antidiagonals, T(n, k) for n, k >= 0.at n=21A143410
• Convolution square of A003106.at n=46A145468
• Numbers k with maximal exponent in prime factorization equal to 1, such that k+1 has maximal exponent 2, k+2 has maximal exponent 3, and k+3 has maximal exponent 4.at n=7A176913
• Semiprime centered triangular numbers.at n=49A184481
• Number of ordered triples (w,x,y) with all terms in {-n,...-1,1,...,n} and w+x+y>=0.at n=19A211612
• Partial sums of A299281.at n=26A299282
• Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of the e.g.f. exp(-x)/(1 - k*x).at n=42A320032
• Numbers k such that 389*2^k+1 is prime.at n=10A323039
• Double subfactorials: a(n) = (-1)^floor(n/2) * n!! * Sum_{i=0..floor(n/2)} (-1)^i/(n-2*i)!!.at n=12A334578
• Triangle read by rows: T(n,k) is the number of symmetries of the n-dimensional hypercube that fix exactly 2*k facets; n,k >= 0.at n=21A342381
• a(n) = Sum_{k=0..floor(n/3)} binomial(3*n-k+1,n-3*k).at n=6A371774
• Triangle read by rows: T(n, k) = n! * 2^k * hypergeom([-k], [-n], -1/2).at n=27A374427
• Truncated hex numbers: a(n) = 24*n^2 + 6*n + 1.at n=34A381424