21748

Appears in sequences

• Fibonacci sequence beginning 1, 13.at n=17A022103
• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 78 ones.at n=33A031846
• Number of partitions of n with equal nonzero number of parts congruent to each of 1 and 2 (mod 4).at n=52A035549
• Number of connected graphs on n labeled nodes that contain at least two cycles.at n=5A140638
• Number of (n+2)X(3+2) 0..3 arrays with every 3X3 subblock row and column sum nonprime and every diagonal and antidiagonal sum prime.at n=5A251840
• Number of (n+2)X(6+2) 0..3 arrays with every 3X3 subblock row and column sum nonprime and every diagonal and antidiagonal sum prime.at n=2A251843
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum nonprime and every diagonal and antidiagonal sum prime.at n=30A251845
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum nonprime and every diagonal and antidiagonal sum prime.at n=33A251845
• G.f.: Sum_{k>=0} A000041(k)^2 * x^k / Sum_{k>=0} A000009(k)^2 * x^k.at n=18A304989