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%I #16 Dec 29 2017 23:24:29
%S 3,4,8,16,16,6,18,24,12,36,18,30,24,72,36,60,48,54,90,72,120,96,108,
%T 180,144,162,78,192,216,360,288,288,120,240,360,150,90,210,270,180,
%U 300,60,540,360,240,480,270,450,90,210,180,420,540,360,600,120,1080,450,270
%N First differences of A293780.
%H Rémy Sigrist, <a href="/A293781/b293781.txt">Table of n, a(n) for n = 1..2260</a>
%H Rémy Sigrist, <a href="/A293781/a293781.png">Colored logarithmic scatterplot of the first 2260 terms</a> (where the color is function of the number of distinct prime factors of A293780(n))
%H Rémy Sigrist, <a href="/A293781/a293781_1.png">Colored logarithmic scatterplot of the first 20000 terms (provided that A293780 is a subsequence of A055932)</a>
%e a(1) = A293780(2) - A293780(1) = 4 - 1 = 3.
%t Block[{s = {1}~Join~Array[Times @@ FactorInteger[#][[All, 1]] &, 10^4, 2], t}, t = 1 + Array[Count[Take[s, # - 1], s[[#]]] &, Length@ s]; Differences@ Map[FirstPosition[t, #][[1]] &, Union@ FoldList[Max, t]]] (* _Michael De Vlieger_, Oct 30 2017 *)
%o (PARI) lista(nn) = {nbm = 0; lastn = 0; v = vector(nn, k, factor(k)[, 1]); for (n=1, nn, vn = vector(n, k, v[k]); nbn = #select(x->(x==v[n]), vn); if (nbn > nbm, if (nbm, print1(n-lastn, ", ")); nbm = nbn; lastn = n;););} \\ _Michel Marcus_, Oct 31 2017
%Y Cf. A055932, A293780.
%K nonn
%O 1,1
%A _David A. Corneth_, Oct 19 2017
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