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Search: id:A130897
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| A130897 |
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a(n) = (sum of digits of a(n-1)) + (product of digits of a(n-1)). |
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+0
1
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| 1, 2, 4, 8, 16, 13, 7, 14, 9, 18, 17, 15, 11, 3, 6, 12, 5, 10, 1, 2, 4, 8, 16, 13, 7, 14, 9, 18, 17, 15, 11, 3, 6, 12, 5, 10, 1, 2, 4, 8, 16, 13, 7, 14, 9, 18, 17, 15, 11, 3, 6, 12, 5, 10, 1, 2, 4, 8, 16, 13, 7, 14, 9, 18, 17, 15, 11, 3, 6, 12, 5, 10, 1, 2, 4, 8, 16, 13, 7, 14, 9, 18, 17, 15
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Sequence is perodic (apparently for any initial a(1)). Fixpoints m, such that A061762(m)=m, are {0,19,29,39,49,59,69,79,89,99} (is this list full?).
Conjecture: sequence is (apart from offset) identical to A036120. Verified for the first 130000 terms. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 13 2008
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FORMULA
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a(n)=A061762(a(n-1)).
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MATHEMATICA
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id[n_]:=IntegerDigits[n]; an1[n_]:=Apply[Plus, id[n]]+Apply[Times, id[n]]; a[1]:=1; a[n_]:=an1[a[n-1]]; ta=Table[a[i], {i, 1, 100}]
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CROSSREFS
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Cf. A061762.
Sequence in context: A070347 A095915 A036120 this_sequence A108565 A066005 A066600
Adjacent sequences: A130894 A130895 A130896 this_sequence A130898 A130899 A130900
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov (zakzeidov(AT)yahoo.com), Aug 22 2007
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