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 A045777 a(1)=1, a(2)=2; thereafter successive products of pairs of digits make further digits. 2
 1, 2, 2, 4, 8, 3, 2, 2, 4, 6, 4, 8, 2, 4, 2, 4, 3, 2, 1, 6, 8, 8, 8, 1, 2, 6, 2, 6, 4, 8, 6, 4, 6, 4, 8, 2, 1, 2, 1, 2, 1, 2, 2, 4, 3, 2, 4, 8, 2, 4, 2, 4, 2, 4, 3, 2, 1, 6, 2, 2, 2, 2, 2, 2, 4, 8, 1, 2, 6, 8, 3, 2, 1, 6, 8, 8, 8, 8, 8, 1, 2, 6, 2, 6, 1, 2, 4, 4, 4, 4, 4, 8, 3, 2, 8, 2, 1, 2, 4, 8, 2, 4, 6, 2, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The numbers 0, 5, 7, and 9 never appear, but arbitrarily long sequences of 8's appear. REFERENCES Erich Friedman, Puzzles of the Week, https://erich-friedman.github.io/mathpuzzle/ LINKS T. D. Noe, Table of n, a(n) for n = 1..15212 EXAMPLE 1*2=2 2*2=4 2*4=8 4*8=32 8*3=24... MATHEMATICA t = {1, 2}; Do[ t = Join[t, IntegerDigits[t[[n-1]] t[[n-2]]]], {n, 3, 100}]; t CROSSREFS Sequence in context: A131199 A112059 A093094 * A136534 A121175 A183397 Adjacent sequences:  A045774 A045775 A045776 * A045778 A045779 A045780 KEYWORD easy,nonn,base AUTHOR STATUS approved

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Last modified May 18 23:31 EDT 2022. Contains 353826 sequences. (Running on oeis4.)