21417

Appears in sequences

• If p(x) is the x-th prime, then the n-th set of 4 consecutive sexy prime pairs starts at p(a(n)).at n=25A095963
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (0, 1, -1), (1, 0, -1), (1, 1, -1), (1, 1, 1)}.at n=8A149642
• Numbers n with property that average digit of n^2 is s=7.at n=17A164773
• Triangle T(n,m) = coefficient of x^n in expansion of (1/2-1/2*(1-8*x)^1/4)^m = sum(n>=m, T(n,m) x^n), n>=1, m>=1.at n=50A202039
• Number of (n+2) X (4+2) 0..3 arrays with every 3 X 3 subblock row and column sum equal to 0 1 3 6 or 7 and every 3X3 diagonal and antidiagonal sum not equal to 0, 1, 3, 6, or 7.at n=5A252188
• Number of (n+2)X(6+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 1 3 6 or 7 and every 3X3 diagonal and antidiagonal sum not equal to 0 1 3 6 or 7.at n=3A252190
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 1 3 6 or 7 and every 3X3 diagonal and antidiagonal sum not equal to 0 1 3 6 or 7.at n=39A252192