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A259047 Composite numbers which divide the concatenation of their prime factors, with multiplicity, in ascending order. 1
28749, 21757820799, 4373079629403 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(2) found by Jens Kruse Andersen who also cleverly derived 119 large terms of the sequence from the factorization of numbers of the form 10^k+1 (see Links).

10^13 < a(4) <= 7810053011863508278028459 (the smallest of J. K. Andersen's large terms).

LINKS

Table of n, a(n) for n=1..3.

Carlos Rivera, Puzzle 472

StackExchange, New term in ascending order

EXAMPLE

4373079629403 is equal to 3*367*2713*1464031 and it is a divisor of 336727131464031, hence it in the sequence.

CROSSREFS

Cf. A248915.

Sequence in context: A213460 A043660 A296814 * A237321 A249957 A157610

Adjacent sequences:  A259044 A259045 A259046 * A259048 A259049 A259050

KEYWORD

nonn,more,base,hard,bref

AUTHOR

Giovanni Resta, Jun 17 2015

STATUS

approved

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Last modified November 26 21:07 EST 2021. Contains 349344 sequences. (Running on oeis4.)