http://list.seqfan.eu/pipermail/seqfan/2010-September/005957.html Yes, A086655 needs a correction to remove that square in the denominator: %I A086655 %N A086655 ( binomial(2*p,p)-2 ) / (2*p) where p is the n-th prime. %F A086655 a(n) = A115112(A000040(n)) / A100484(n).