97713

Appears in sequences

• Number of noninvertible 2 X 2 matrices over Z/nZ (determinant is a divisor of 0).at n=19A020479
• Heptagonal numbers with only odd digits.at n=12A117993
• Heptagonal numbers A000566 which are the sum of two other heptagonal numbers > 0.at n=30A133251
• Rectangular array A read by upward antidiagonals: A(n,m) is the number of total difunctional (regular) binary relations between an n-element set and an m-element set.at n=49A265706
• Rectangular array A read by upward antidiagonals: A(n,m) is the number of surjective difunctional (regular) binary relations between an n-element set and an m-element set.at n=50A265707
• Triangular array T(n,k), read by rows: coefficients of strong divisibility sequence of polynomials p(1,x) = 1, p(2,x) = 1 + 3x, p(n,x) = u*p(n-1,x) + v*p(n-2,x) for n >=3, where u = p(2,x), v = 2 - x^2.at n=50A368151