18155

Appears in sequences

• Number of terms in a symmetrical determinant: a(n) = n*a(n-1) - (n-1)*(n-2)*a(n-3)/2.at n=8A002135
• Numbers k such that 3*10^k + 7*R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=5A056705
• Number of permutations of 1..n containing the relative rank sequence { 134526 } at any spacing.at n=3A159093
• Number of permutations of 1..n containing the relative rank sequence { 143652 } at any spacing.at n=3A159112
• Number of permutations of 4 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/2)] (2-way heap).at n=3A178022
• Numbers n for which the digital sum contains the same distinct digits as the digital product but the digital sum is not equal to the digital product.at n=28A249335
• Number A(n,k) of factorizations of m^k into n factors, where m is a product of exactly n distinct primes and each factor is a product of k primes (counted with multiplicity); square array A(n,k), n>=0, k>=0, read by antidiagonals.at n=63A257463
• Triangle read by rows: Cayley's numbers phi(m,n) (m,n>=0). Row m contains phi(m,0), phi(m-1,1), phi(m-2,2), ..., phi(0,m).at n=36A260338
• Coefficient of x^2 in minimal polynomial of the continued fraction [1^n,4,1,1,1,...], where 1^n means n ones.at n=9A265802
• Expansion of (x+4*x^4)/(1-x-x^2-x^4-2*x^5-x^8).at n=17A270879
• Number of primes of the form b^2+1 for b <= 10^n that end in 1.at n=5A301943
• Numbers k such that 459*2^k+1 is prime.at n=40A323199
• Array read by antidiagonals: T(n,k) is the number of k-regular multigraphs on n labeled nodes, loops allowed, n >= 0, k >= 0.at n=63A333467