A293781 - OEIS

A293781

First differences of A293780.

3, 4, 8, 16, 16, 6, 18, 24, 12, 36, 18, 30, 24, 72, 36, 60, 48, 54, 90, 72, 120, 96, 108, 180, 144, 162, 78, 192, 216, 360, 288, 288, 120, 240, 360, 150, 90, 210, 270, 180, 300, 60, 540, 360, 240, 480, 270, 450, 90, 210, 180, 420, 540, 360, 600, 120, 1080, 450, 270

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..2260

Rémy Sigrist, Colored logarithmic scatterplot of the first 2260 terms (where the color is function of the number of distinct prime factors of A293780(n))

Rémy Sigrist, Colored logarithmic scatterplot of the first 20000 terms (provided that A293780 is a subsequence of A055932)

EXAMPLE

a(1) = A293780(2) - A293780(1) = 4 - 1 = 3.

MATHEMATICA

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 *)

PROG

(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

CROSSREFS

Cf. A055932, A293780.

Sequence in context: A007486 A027977 A165438 * A202025 A227615 A049894

Adjacent sequences: A293778 A293779 A293780 * A293782 A293783 A293784

KEYWORD

nonn

AUTHOR

David A. Corneth, Oct 19 2017

STATUS

approved