305085

Appears in sequences

• Number of compositions p(1)+p(2)+...+p(k) = n such that for no part p(i) = i (compositions without fixed points).at n=21A238351
• a(n) is the sum of n consecutive triangular numbers immediately preceding a triangular number T(k), which is also equal to the sum of n-1 consecutive triangular numbers immediately following T(k).at n=10A392441