-2190

Appears in sequences

• A generalized Catalan number sequence.at n=18A174015
• a(0) = 1, a(1) = 2, a(2) = 3; thereafter, a(n) = a(n-1) + (sum of prior prime terms or whose negatives are prime) - (sum of prior composite terms or whose negatives are composite).at n=27A381150