1596291840

Appears in sequences

• Number of pairs of orthogonal (-4,5) vectors of length 9*n.at n=1A225996
• For n > 1, if n appears in the sequence then a(n) = lastindex(n), where lastindex(n) is the index of the last appearance of n. Otherwise a(n+1) = a(n)/(n+1) if (n+1)|a(n), otherwise a(n)*(n+1), a(1) = 1 and a(2) = 1*2.at n=19A362332