18425

Appears in sequences

• a(1) = 3; a(n+1) = a(n)-th composite.at n=37A022451
• Numerators of continued fraction convergents to sqrt(886).at n=8A042712
• Expansion of (1-x+7x^2)/((1-x)(1-2x)).at n=12A154251
• a(n) = 1331*n - 209.at n=13A157444
• G.f.: A(x) = Sum_{n>=0} x^n * (1+x)^A038722(n), where A038722(n) = floor(sqrt(2*n)+1/2)^2 - n + 1.at n=20A192316
• Number of ordered triples (w,x,y) with all terms in {-n,...-1,1,...,n} and w+x+y>1.at n=17A211613
• Triangle read by rows, arising in enumeration of permutations by cyclic peaks.at n=17A216962
• Triangle read by rows, related to Bell numbers A000110: A216962 interlaced with A216964.at n=30A217204
• G.f. satisfies: A(x) = exp( Sum_{n>=1} x^n/n * Sum_{k=0..2*n} A084606(n,k)^2 * x^k * A(x)^k ), where A084606(n,k) = [x^k] (1 + 2*x + 2*x^2)^n.at n=7A218299
• Numbers m > 0 that have a divisor d > 1 with binomial(m+d, d) == 1 mod m.at n=31A290040
• Numbers k such that (115*10^k - 7)/9 is prime.at n=15A295083
• Triangle T(n,k) of number of chains of length k in partitions of an n-set ordered by refinement.at n=30A331955
• a(2*n) = 9*2^n - 7, a(2*n+1) = 3*2^(n+2) - 7.at n=22A354789
• a(n) = Sum_{d|n} (-1)^(n/d-1) * binomial(d+2,3).at n=46A366813