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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, http://www2.stetson.edu/~efriedma/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

Erich Friedman

STATUS

approved

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Last modified August 21 13:36 EDT 2017. Contains 290890 sequences.