18122

Appears in sequences

• Convolution of the lower and upper Wythoff sequences (A000201 and A001950).at n=28A023664
• a(n) = binomial(2*n-1, n) - binomial(2*n-1, n+3).at n=8A026016
• a(n) = T(n, [n/2]), where T is the array defined in A026009.at n=17A026021
• Base-2 digital convolution sequence.at n=42A033639
• T(n, k) = S(2*n + 1, n, k + 1) for 0<=k<=n and n >= 0, array S as in A050157.at n=38A050158
• T(n,k) = S(2n-1,n-1,k-1), 0<=k<=n, n >= 0, array S as in A050157.at n=48A050159
• Numbers n such that 125*2^n-1 is prime.at n=10A050588
• Expansion of (1+x^2*C^4)*C, where C = (1 - sqrt(1-4*x))/(2*x) is g.f. for Catalan numbers, A000108.at n=9A071725
• Inverse of Riordan array (1/(1+x+x^2),x/(1+x)^2).at n=46A122919
• Twice 13-gonal numbers: a(n) = n*(11*n - 9).at n=41A152997
• Nonnegative numbers n such that 6*2^n-1 is prime.at n=32A164523
• Number of nX2 0..1 arrays with no adjacent rows or columns having the same least squares slope fit to a straight line, with a single point array taken as having zero slope.at n=9A223150
• Numbers that can be represented as a sum of two distinct nontrivial prime powers in three or more ways.at n=18A225104
• Numbers which are the sum of two squared primes in exactly three ways (ignoring order).at n=6A226562
• G.f. satisfies: A(x*A(-x)) = C(x), where C(x) = 1 + x*C(x)^2 is the Catalan function of A000108.at n=9A244278
• Numbers k that are the product of four distinct primes such that x^2+y^2 = k has integer solutions.at n=29A248712
• Expansion of f(-x^3, -x^5) * f(x^3, x^13) / (f(-x, -x^2) * f(-x^8, -x^16)) in powers of x where f(, ) is Ramanujan's general theta function.at n=43A258939
• a(n) = (n^2 + 1) * (2*n - 1).at n=20A290631