88996domain: NAppears in sequencesNumbers n, not divisible by 3, 5, 7 or 11, such that A000203(n)-n-1 and 2*n+1-A000203(n) are prime numbers.at n=27A180268Expansion of (1/(1 - x)) * Sum_{k>=0} x^(2*k+1) / Product_{j=1..2*k+1} (1 - x^j).at n=39A306145