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A263413 Largest prime (or noncomposite) factor of the Crandall number A262961(n). 2
0, 1, 2, 5, 151, 661, 521, 49993, 858868651, 115523, 72920757563, 3844109, 1637177, 7158605959, 17024617, 13062611, 66113257898351335849, 599880481206897379, 745125370039, 4314028165895642655831229, 30699710580827, 1744795596758086587163381, 2463356705098399667815003 (list; graph; refs; listen; history; text; internal format)
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

(PARI) a(n)=A006530(A262961(n)) \\ M. F. Hasler, Oct 17 2015

CROSSREFS

Cf. A262961.

Sequence in context: A155762 A307480 A062611 * A270585 A041505 A116629

Adjacent sequences:  A263410 A263411 A263412 * A263414 A263415 A263416

KEYWORD

nonn,hard

AUTHOR

M. F. Hasler, Oct 17 2015

STATUS

approved

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Last modified July 31 06:15 EDT 2021. Contains 346369 sequences. (Running on oeis4.)