76480

Appears in sequences

• Octagonal numbers which are the sums of exactly two positive octagonal numbers.at n=32A136346
• 100-gonal numbers: a(n) = 98*n*(n-1)/2 + n.at n=40A261276
• a(n) is the least number k such that the equation phi(x) = k has exactly n solutions and the arithmetic mean of these solutions is an integer, or -1 if no such number exists.at n=25A389860