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 A036325 Composite numbers n such that digits of prime factors of n are either 8 or 9. 26
 7921, 704969, 800911, 8001011, 8009021, 8802011, 8810911, 8899021, 62742241, 71281079, 79120021, 80001121, 80982001, 88109911, 88910021, 712089979, 712802869, 783378979, 784171079, 791120021, 791200121, 792012869, 800020021, 800109911, 800901121, 800991011, 809001101, 809811011, 880111121 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are a product of at least two terms of A020472. - David A. Corneth, Apr 30 2018 LINKS David A. Corneth, Table of n, a(n) for n = 1..10000 (first 5375 terms from Robert Israel) EXAMPLE 7921 is in the sequence because it's composite and its distinct prime factors are 89, only having digits 8 or 9. - David A. Corneth, Apr 30 2018 MAPLE N:= 9: # to get all terms of <= N digits R:= 10^N: G:= {9}: S:= {1}: for n from 1 to N-1 do   G:= map(t -> (t+8*10^n, t+9*10^n), G);   newprimes:= select(isprime, G);   for p in newprimes do     S:= map(s -> seq(s*p^i, i=0..floor(log[p](R/s))), S)   od od: sort(convert(remove(isprime, S minus {1}), list)); # Robert Israel, Apr 30 2018 CROSSREFS Cf. A020472, A036302-A036324. Sequence in context: A121236 A233976 A001228 * A031587 A031767 A250629 Adjacent sequences:  A036322 A036323 A036324 * A036326 A036327 A036328 KEYWORD nonn,easy,base AUTHOR Patrick De Geest, Dec 15 1998 EXTENSIONS More terms from Robert Israel, Apr 29 2018 STATUS approved

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Last modified November 25 11:32 EST 2020. Contains 338623 sequences. (Running on oeis4.)