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 A075517 Created by removing all integers which take an odd number of nested digit sums to reach <10. 3
 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 19, 28, 29, 37, 38, 39, 46, 47, 48, 49, 55, 56, 57, 58, 59, 64, 65, 66, 67, 68, 69, 73, 74, 75, 76, 77, 78, 79, 82, 83, 84, 85, 86, 87, 88, 89, 91, 92, 93, 94, 95, 96, 97, 98, 99, 109, 118, 119, 127, 128, 129, 136, 137, 138, 139, 145, 146, 147 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 0..10000 EXAMPLE 18 -> 1+8 = 9. This takes 1 step to be reduced to a single integer, hence is not in the sequence. 99 -> 9+9 = 18, takes 2 steps and so is in the sequence. MATHEMATICA ondQ[n_]:=OddQ[Length[NestWhileList[Total[IntegerDigits[#]]&, n, #>9&]]]; Select[Range[0, 200], ondQ] (* Harvey P. Dale, Dec 22 2016 *) PROG (PARI) sumdigits(n)=local(c); c=0; while (n>0, c=c+n%10; n=n-n%10; n=n/10); c checkSieve(n)=local(c); c=0; while(n>9, n=sumdigits(n); c++); 1-c%2 for (n=1, 2000, if (checkSieve(n), print1(n, ", "))) (Haskell) a075517 n = a075517_list !! n a075517_list = [0..9] ++ f 1 [0..9] where f x ys = if a007953 x `elem` ys then f (x + 1) ys else x : f (x + 1) (x : ys) -- Reinhard Zumkeller, Sep 29 2014, Apr 22 2012 CROSSREFS Cf. A007953, A075311. Sequence in context: A087052 A077557 A332261 * A248013 A088473 A317110 Adjacent sequences: A075514 A075515 A075516 * A075518 A075519 A075520 KEYWORD nonn,base AUTHOR Jon Perry, Oct 11 2002 EXTENSIONS Offset fixed by Reinhard Zumkeller, Apr 22 2012 Added a(0) = 0. - Jon Perry, Nov 28 2012 STATUS approved

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Last modified December 5 23:11 EST 2023. Contains 367594 sequences. (Running on oeis4.)