3964051

Appears in sequences

• a(n) = 7*a(n-1) - 14*a(n-2) + 7*a(n-3), a(0)=0, a(1)=1, a(2)=5.at n=12A215008
• a(n) = Sum_{k=0..floor(n/7)} (-1)^k*binomial(n,7*k).at n=25A307041
• a(n) is the smallest centered n-gonal number with exactly n prime factors (counted with multiplicity).at n=3A358926