18624

Appears in sequences

• Number of partitions with no even part repeated; partitions of n in which no parts are multiples of 4.at n=43A001935
• Star of David matchstick numbers: a(n) = 6*n*(3*n+1).at n=32A045946
• Number of partitions of 2n+1 in which no parts are multiples of 4.at n=21A081056
• Expansion of -(1-x-2*x^2+11*x^4-3*x^3) / ((x-1)*(x+1)*(x^2-3*x+1)*(1+x^2)).at n=11A109787
• Indices m such that A128646(m)-1 is prime, where A128646 = denominator of partial sums of 1/(p(i)-1).at n=48A137689
• Number of line segments connecting exactly 7 points in an n X n grid of points.at n=37A177723
• Number of n X n matrices over GF(2) that can be used as a kernel to construct a polar code. That is, the number of matrices for which channel polarization occurs.at n=3A187880
• Smallest integer k such that k*n+1 is a prime dividing (n^n)^2 + 1.at n=21A208400
• a(n) = (prime(n)^2 - 1)/2 for n >= 2.at n=42A216244
• Number of (n+1) X (5+1) 0..3 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 3 (constant-stress 1 X 1 tilings).at n=5A235295
• Number of (n+1) X (6+1) 0..3 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 3 (constant-stress 1 X 1 tilings).at n=4A235296
• Numbers such that the largest prime factor equals the sum of the 4th power of the other prime factors.at n=14A244344
• Expansion of phi(-x^3) * psi(-x^3) / phi(-x)^2 in powers of x where phi(), psi() are Ramanujan theta functions.at n=14A260546
• Least common multiple of prime(n+1)+1 and prime(n)+1.at n=42A309772
• Number of necklace compositions of n with distinct differences.at n=24A325554
• Irregular table read by rows: Take a diagonal-edged (or diamond-shaped) checkerboard with all diagonals drawn, as in A333434. Then T(n,k) = number of k-sided polygons in that figure for k >= 3.at n=33A333458
• Let ped(n) denote the number of partitions of n in which the even parts are distinct (A001935); a(n) = ped(9*n+7).at n=4A340508
• Primitive Pythagorean triples [a, b, c] in lexicographic order with a < b < c such that [w(a), w(b), w(c)] is also a primitive Pythagorean triple, where w(n) is the binary weight of n.at n=61A349120
• Indices of records in A378865.at n=19A385290
• a(n) is the least number k such that the equation phi(x) = k has exactly n solutions and the arithmetic mean of these solutions is an integer, or -1 if no such number exists.at n=20A389860