reviewed
approved
proposed
editing
Cf. A000326, A186424, A193832.
a(n) = (A000326(2n-1) + A000326(2n))/2. - Charlie Marion, Apr 17 2024
By Pick's theorem, a(n) = 6*n^2 - 4*n + 1. - . - _Nick Hobson (nickh(AT)qbyte.org), _, Mar 13 2007