22640

Appears in sequences

• Number of self-avoiding polygons of area n with 3 (self-avoiding polygon) holes on square lattice (not allowing rotations).at n=3A057408
• When A032523 is a maximum; or, A091657 less duplicates.at n=17A091658
• a(n+3) = 2*a(n+2) + 3*(n+1) - a(n).at n=9A095310
• Index of first occurrence of n-th prime in A001203, the continued fraction for Pi.at n=26A107892
• Expansion of x * (1-x) / ( 1 - 2*x - 3*x^2 + x^3 ).at n=11A122299
• Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 1), (-1, 0), (0, 1), (1, -1), (1, 1)}.at n=7A151310
• Number of 6X6 arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to n.at n=38A156389
• Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 38.at n=3A156502
• Convolved with its aerated variant of two zeros between terms = A000041.at n=47A174068
• Number of (n+2)X(n+2) symmetric binary matrices without the pattern 0 1 1 vertically, antidiagonally or horizontally.at n=3A190534
• Least k such that k*6^n-1 , k*6^n+1, and 2*k*6^n-1 are prime; that is, twin primes and a Sophie Germain prime.at n=36A212481
• a(n) is the number of solutions to the "sum equals product" riddle with n prices v_j, i.e., find positive integers v_j, v_{j+1}>=v_j such that 100^(n-1)*Sum_{k=1..n} v_k = Product_{k=1..n} v_k.at n=3A382510