a(0) = 1; thereafter a(n) is the smallest prime divisor of the number C(6n+1) formeded from the concatenation of 1,2,3,...,6n+1.

A320571

a(0) = 1; thereafter a(n) is the smallest prime divisor of the number C(6n+1) formeded from the concatenation of 1,2,3,...,6n+1.

Terms

    a(0) =1a(1) =127a(2) =113a(3) =13a(4) =5a(5) =29a(6) =71a(7) =7a(8) =23a(9) =5a(10) =10386763a(11) =397a(12) =37907a(13) =73a(14) =5a(15) =37a(16) =13a(17) =131a(18) =7a(19) =5a(20) =278240783a(21) =53a(23) =13a(24) =5a(25) =7a(26) =11a(27) =2381a(28) =2671a(29) =5a(30) =31

External references