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A262229 Numbers m such that A000217(m) > A062918(m). 1

%I

%S 10,11,87,88,90,91,92,93,94,95,96,97,98,99,100,101,102,103,895,896,

%T 897,898,899,900,901,902,903,904,905,906,907,908,909,910,911,912,913,

%U 914,915,916,917,918,919,920,921,922,923,924,925,926,927,928,929,930,931

%N Numbers m such that A000217(m) > A062918(m).

%C The sum of the digit reversals of first n natural numbers (A062918) is equal to the sum of the first n natural numbers (A000217) for n=1 to 9. Then 10 is the first time that A000217(m) > A062918(m).

%H Michel Marcus, <a href="/A262229/b262229.txt">Table of n, a(n) for n = 1..1274</a>

%H Didier Müller, <a href="http://www.nymphomath.ch/turing/probleme.php?id=131">Somme des premiers entiers inversés</a>, Défi Turing (in French).

%e For m=10, 1+2+3+4+5+6+7+8+9+10 is > 1+2+3+4+5+6+7+8+9+01, so 10 is a term.

%t lim = 931; t = Rest@ Accumulate[Range[0, lim]]; s = Accumulate[Table[FromDigits[Reverse[IntegerDigits@ n]], {n, 1, lim + 1}]];Select[Range@ lim, t[[#]] > s[[#]] &] (* _Michael De Vlieger_, Sep 15 2015, after _Harvey P. Dale_ at A000217 and _Enrique Pérez Herrero_ at A062918 *)

%o (PARI) isok(n) = n*(n+1)/2 - sum(k=1,n, eval(concat(Vecrev(Str(k))))) > 0;

%o (MAGMA) [m: m in [0..10^3] | m*(m+1)/2 gt &+[Seqint(Reverse(Intseq(i))): i in [0..m]]]; // _Bruno Berselli_, Sep 16 2015

%Y Cf. A000217, A062918.

%K nonn,base

%O 1,1

%A _Michel Marcus_, Sep 15 2015

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Last modified February 23 07:06 EST 2018. Contains 299473 sequences. (Running on oeis4.)