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A304373
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Numbers n with additive persistence = 4.
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4
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19999999999999999999999, 28999999999999999999999, 29899999999999999999999, 29989999999999999999999, 29998999999999999999999, 29999899999999999999999, 29999989999999999999999, 29999998999999999999999, 29999999899999999999999, 29999999989999999999999
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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Repeatedly taking the sum of digits starting with 19999999999999999999999 gives 199, 19, 10 and 1. There are four steps, so the additive persistence is 4 and 19999999999999999999999 is a member.
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MATHEMATICA
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Take[ Sort@ Flatten[ (FromDigits /@ Permutations@#) & /@ IntegerPartitions[ 199, {23}, Range@ 9]], 10000] (* first 10000 terms, Giovanni Resta, May 29 2018 *)
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PROG
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(PARI) nb(n) = {my(nba = 0); while (n > 9, n = sumdigits(n); nba++); nba; }
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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