69113domain: NAppears in sequencesa(n) is the smallest number which is the sum of two positive n-gonal numbers in more than one way.at n=26A199809Composite squarefree numbers n such that p(i)-7 divides n+7, where p(i) are the prime factors of n.at n=26A225707E.g.f. A(x) satisfies A(x) = exp( sin(x * A(x)^2) / A(x)^2 ).at n=8A381413