20975

Appears in sequences

• Number of asymmetric mobiles (circular rooted trees) with n nodes and 3 leaves.at n=29A055364
• a(n) = pq + pr + qr with p = prime(n), q = prime(n+1), and r = prime(n+2).at n=21A127345
• Composites in A127345.at n=11A127347
• a(n) = 839*n.at n=25A135639
• Number of (n+1) X (6+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=1A253493
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=22A253495
• Number of (2+1) X (n+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=5A253496
• Number of factorizations of m^n into exactly six factors, where m is a product of two distinct primes.at n=10A277242
• Number of nX4 0..1 arrays with every element equal to 0, 2, 3, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=9A303238
• Trajectory of n under the Reverse and Add! operation carried out in base 8 (presumably) does not reach a palindrome and (presumably) does not join the trajectory of any term m < n.at n=30A306596
• Number of series-reduced achiral free pure multifunctions (with empty expressions allowed) with one atom and n positions.at n=18A317884
• Denominator of harmonic mean of 3 consecutive primes. Numerators are A331259.at n=21A331260
• On a spirally numbered square grid, with labels starting at 1, this is the number of steps that an (n,n+1) leaper makes before getting trapped, or -1 if it never gets trapped.at n=18A343178