A263413 - OEIS

A263413

Largest prime (or noncomposite) factor of the Crandall number A262961(n).

0, 1, 2, 5, 151, 661, 521, 49993, 858868651, 115523, 72920757563, 3844109, 1637177, 7158605959, 17024617, 13062611, 66113257898351335849, 599880481206897379, 745125370039, 4314028165895642655831229, 30699710580827, 1744795596758086587163381, 2463356705098399667815003

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OFFSET

1,3

COMMENTS

Computed up to n = 94 by David Broadhurst, and independently up to n = 67 by Hans Havermann and M. F. Hasler.

At n = 95 and n = 96 we have composite factors of 157 digits with probably no divisor less than 50 digits. - David Broadhurst, Oct 17 2015

LINKS

David Broadhurst, Table of n, a(n) for n = 1..94

Hans Havermann and David Broadhurst, Crandall Numbers Factored

FORMULA

a(n) = A006530(A262961(n)).

PROG