a(n) is the least k such that A051903(k^2+1) = n.

Terms

a(0) =1a(1) =7a(2) =57a(3) =182a(4) =2057a(5) =1068a(6) =32318a(7) =110443a(8) =280182a(9) =3626068a(10) =23157318a(11) =120813568a(12) =123327057a(13) =1097376068a(14) =11109655182a(15) =49925501068a(16) =407838170807a(17) =355101282318