21128

Appears in sequences

• a(n+1) = Sum_{k=0..floor(n/4)} a(k) * a(n-k).at n=20A030034
• Number of n-celled free polyominoes with 1 hole.at n=6A057418
• Satisfies a(n)/A079159(n) = p_n, the n-th prime (n>0), a(0)=1.at n=34A079161
• Consider the triangle shown below; sequence contains the concatenation of numbers read at a 45-degree angle upwards with horizontal beginning with the first term of a row.at n=5A079826
• n*(1+3*n+6*n^2)/2.at n=19A115519
• Number of (6+2)X(n+2) 0..1 arrays with every 3X3 subblock sum of the two sums of the diagonal and antidiagonal minus the two minimums of the central column and central row nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=10A254912
• Number of ways to split an integer partition of n into contiguous subsequences with weakly increasing sums.at n=27A336136
• 32-gonal numbers: a(n) = n*(15*n-14).at n=38A360436