Integers n such that A047988(n)=3.

Terms

a(0) =173a(1) =347a(2) =823a(3) =907a(4) =1237a(5) =1697a(6) =2137a(7) =2333a(8) =2423a(9) =2473a(10) =2767a(11) =2777a(12) =3253a(13) =3413a(14) =3547a(15) =3559a(16) =3623a(17) =3767a(18) =4243a(19) =4273a(20) =4457a(21) =4547a(22) =4723a(23) =5091a(24) =5297a(25) =5861a(26) =6185a(27) =6197a(28) =6593a(29) =6823