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A036323 Composite numbers n such that digits of prime factors of n are either 7 or 8. 2
49, 343, 2401, 5509, 6139, 6209, 16807, 38563, 42973, 43463, 55139, 62209, 117649, 269941, 300811, 304241, 385973, 435463, 551509, 552139, 552209, 615139, 615209, 619369, 690199, 698069, 769129, 777899, 786769, 823543, 1889587, 2105677 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are a product of at least two terms of A020470. - David A. Corneth, Oct 09 2020

LINKS

David A. Corneth, Table of n, a(n) for n = 1..10000

Index entries for sequences related to prime factors

MATHEMATICA

Select[Range[25*10^5], CompositeQ[#]&&SubsetQ[{7, 8}, Flatten[ IntegerDigits/@ Transpose[ FactorInteger[#]][[1]]]]&] (* Harvey P. Dale, Jan 19 2015 *)

CROSSREFS

Cf. A020470, A036302-A036325.

Sequence in context: A211736 A211747 A211756 * A066429 A269327 A206255

Adjacent sequences:  A036320 A036321 A036322 * A036324 A036325 A036326

KEYWORD

nonn,easy,base

AUTHOR

Patrick De Geest, Dec 15 1998

STATUS

approved

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Last modified January 22 05:13 EST 2021. Contains 340360 sequences. (Running on oeis4.)