The list of the a(n)-values in the common solutions to k+1=b^2 and 6*k+1=a^2.

Terms

a(0) =1a(1) =7a(2) =17a(3) =71a(4) =169a(5) =703a(6) =1673a(7) =6959a(8) =16561a(9) =68887a(10) =163937a(11) =681911a(12) =1622809a(13) =6750223a(14) =16064153a(15) =66820319a(16) =159018721a(17) =661452967a(18) =1574123057a(19) =6547709351a(20) =15582211849a(21) =64815640543a(22) =154247995433a(23) =641608696079