Primes p such that there exists a prime q < p such that sigma(p-1) = sigma(q-1) = p + q.

Terms

a(0) =1163a(1) =7583a(2) =17099a(3) =48857a(4) =65963a(5) =172859a(6) =5408423a(7) =6804047a(8) =19247087a(9) =73162367a(10) =77695043a(11) =109775657a(12) =109871933a(13) =116464757a(14) =160454717a(15) =175031957a(16) =175288493a(17) =218543393a(18) =268382183a(19) =303220769a(20) =379299989a(21) =705800723a(22) =823155779a(23) =889218389a(24) =967371143a(25) =1100618483a(26) =1242282407a(27) =1701133163