Numbers k for which 10k+1, 10k+3, 10k+7 and 10k+9 are primes.

Terms

a(0) =1a(1) =10a(2) =19a(3) =82a(4) =148a(5) =187a(6) =208a(7) =325a(8) =346a(9) =565a(10) =943a(11) =1300a(12) =1564a(13) =1573a(14) =1606a(15) =1804a(16) =1891a(17) =1942a(18) =2101a(19) =2227a(20) =2530a(21) =3172a(22) =3484a(23) =4378a(24) =5134a(25) =5533a(26) =6298a(27) =6721a(28) =6949a(29) =7222