Primes p of the form sigma(2k-1) for a number k.

Terms

a(0) =13a(1) =31a(2) =307a(3) =1093a(4) =1723a(5) =2801a(6) =3541a(7) =5113a(8) =8011a(9) =10303a(10) =17293a(11) =19531a(12) =28057a(13) =30103a(14) =30941a(15) =86143a(16) =88741a(17) =147073a(18) =292561a(19) =459007a(20) =492103a(21) =552793a(22) =579883a(23) =598303a(24) =684757a(25) =704761a(26) =732541a(27) =735307a(28) =797161a(29) =830833