A073844 a(1) = 1, a(n) = largest prime divisor of A057137(n).

1, 3, 41, 617, 823, 643, 9721, 14593, 3803, 3803, 14405693, 10288065751, 116216501, 12079920647, 7552031, 435503, 1763668414462081, 106377431, 27961, 27961, 205126079, 84225392753, 7347135846537257, 437274720469, 12792129877, 244251294564157

Offset

1,2

Links

Daniel Suteu, Table of n, a(n) for n = 1..167

Formula

a(n) = A006530(A057137(n)). - Michel Marcus, May 26 2022

Prog

(PARI) a(n) = if(n==1, 1, vecmax(factor(sum(i=1, n, i%10*10^(n-i)))[, 1])); \\ Daniel Suteu, May 25 2022

Crossrefs

Cf. A006530, A057137.

Sequence in context: A213378 A189356 A155672 * A138961 A075022 A367981

Adjacent sequences: A073841 A073842 A073843 * A073845 A073846 A073847

Keyword

nonn

Author

Jason Earls, Sep 02 2002

Status

approved