393828

Appears in sequences

• a(1) = 1, a(2) = 1, a(n) = sum of tau(n) previous terms, where tau(n) is the number of divisors of n.at n=22A087549
• a(n) is the smallest number which can be represented as the sum of n distinct nonzero n-gonal pyramidal numbers in exactly n ways, or -1 if no such number exists.at n=19A350397