18123

Appears in sequences

• Numbers m such that 3*2^m - 1 is prime.at n=33A002235
• Number of isomers of polyhex hydrocarbons with C_(2v) symmetry with nineteen hexagons.at n=19A120448
• Let y = y(u,v) be implicitly defined by g(u,v,y(u,v)) = 0. Read as a triangle by rows k = 1,2,..., the sequence represents the number of terms a(i,k-i) in the expansion of the partial derivatives d^k y/du^i dv^{k-i} in terms of partial derivatives of g.at n=48A172004
• Let y = y(u,v) be implicitly defined by g(u,v,y(u,v)) = 0. Read as a triangle by rows k = 1,2,..., the sequence represents the number of terms a(i,k-i) in the expansion of the partial derivatives d^k y/du^i dv^{k-i} in terms of partial derivatives of g.at n=49A172004
• Position of start of first appearance of n consecutive 1's in the binary expansion of Pi.at n=11A178709
• Position of start of first appearance of n consecutive 1's in the binary expansion of Pi.at n=12A178709
• Number of 0..3 arrays x(0..n-1) of n elements with nondecreasing average value and 0..3 occur with instance counts within one of each other.at n=19A200939
• Number of Dyck n-paths all of whose ascents and descents have lengths equal to 1 (mod 8).at n=33A212367
• Numbers k such that 43^k + 4 is prime.at n=13A230433
• a(n) = Sum_{i=0..n} digsum_8(i)^4, where digsum_8(i) = A053829(i).at n=21A231683
• Number T(n,k) of proper k-times partitions of n; triangle T(n,k), n >= 0, 0 <= k <= max(0,n-1), read by rows.at n=42A327639
• Number of ways to write n as an ordered sum of 7 nonzero decimal palindromes.at n=12A341204
• Diagonal Donaldson-Thomas invariants for the Kronecker quiver K3.at n=6A345134
• Numbers k such that (k*2^d - 1)*(d*2^k - 1) is semiprime for some divisor d of k.at n=43A382646