Primes p such that sigma(p-1)+sigma(p+1) is prime.

Terms

a(0) =2a(1) =5a(2) =37a(3) =101a(4) =257a(5) =401a(6) =4801a(7) =12101a(8) =22501a(9) =25537a(10) =25601a(11) =31249a(12) =33857a(13) =160001a(14) =217157a(15) =401957a(16) =404497a(17) =476101a(18) =512657a(19) =583697a(20) =1020101a(21) =1270417a(22) =1322501a(23) =1503377a(24) =1674437a(25) =1943237a(26) =2005057a(27) =2016401a(28) =2056357a(29) =2689601