a(n) = smallest index m such that smallest prime factor of m-th triangular number is prime(n).

Terms

a(0) =3a(1) =2a(2) =10a(3) =13a(4) =22a(5) =298a(6) =526a(7) =37a(8) =46a(9) =58a(10) =61a(11) =73a(12) =82a(13) =3397a(14) =2866a(15) =106a(16) =3481a(17) =3721a(18) =5293a(19) =5041a(20) =7081a(21) =157a(22) =166a(23) =178a(24) =193a(25) =10201a(26) =14317a(27) =23326a(28) =23761a(29) =226