18347

Appears in sequences

• Integers n > 1997 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 1997.at n=34A063055
• Triangle of coefficients, read by rows of (2n+1) terms, where the n-th row forms a polynomial in x, P(n,x), of degree 2n and satisfies: P(n,x) = [Sum_{k=1..n} 1/(k + x + x^2)]*[Product_{k=1..n} (k + x + x^2)].at n=42A074248
• Interprimes which are of the form s*prime, s=7.at n=20A075282
• Triangle read by rows: T(n,k) is the number of skew Dyck paths of semilength n and having k LL's (n >= 0; 0 <= k <= n-2 for n >= 2).at n=40A128724
• Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1100-0111-0010 pattern in any orientation.at n=14A146457
• Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 0010-1110-0111-0100 pattern in any orientation.at n=17A146907
• a(n) = (a(n-1) + a(n-3))/gcd(a(n-1), a(n-3)) with a(0) =2, a(1) = 3, a(2) = 5.at n=53A214331
• Numbers k such that (13*10^k + 311)/9 is prime.at n=16A295031
• Expansion of e.g.f. ( Product_{k>0} 1/(1-x^k)^(1/k!) )^(1/(1-x)).at n=6A356025