129404

Appears in sequences

• Number of regions in regular n-gon with all diagonals drawn.at n=43A007678
• a(1) = 1, a(2) = 2; for n > 1, a(n) = sum of the next two smallest integers > a(n-1) which are coprime to the sum s = a(1) + ... + a(n-1).at n=15A131357
• Expansion of e.g.f. 1 / ( 1 - Sum_{k>=0} x^(2*k+5) / (2*k+5)! ).at n=18A365915
• Symmetric difference of the primitive non-deficient numbers and the primitive Zumkeller numbers.at n=43A378538
• Numbers that are primitive Zumkeller, but not primitive non-deficient.at n=33A378657