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A113458 Least k such that k, k+n and k+2n have the same prime signature. 3
33, 3, 155, 3, 77, 5, 51, 3, 77, 3, 35, 5, 50, 3, 187, 6, 21, 5, 39, 3, 145, 33, 39, 5, 69, 39, 91, 3, 33, 7, 15, 12, 221, 3, 28, 7, 21, 3, 55, 3, 33, 5, 91, 66, 209, 69, 35, 5, 50, 3, 115, 39, 141, 5, 51, 6, 145, 85, 15, 7, 21, 93, 95, 3, 57, 5, 51, 3, 65, 15, 35, 7, 69, 55, 287, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Third row of A113456.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..20000

EXAMPLE

a(4) = 3 because 3, 7 and 11 have the same prime signature.

MAPLE

s:= n-> sort(map(i-> i[2], ifactors(n)[2])):

a:= proc(n) option remember; local k; for k

      while s(k)<>s(k+n) or s(k)<>s(k+2*n) do od; k

    end:

seq(a(n), n=1..100);  # Alois P. Heinz, Feb 28 2018

CROSSREFS

Cf. A052214, A113456, A113467.

Sequence in context: A032445 A135088 A113467 * A120584 A236177 A123173

Adjacent sequences:  A113455 A113456 A113457 * A113459 A113460 A113461

KEYWORD

easy,nonn

AUTHOR

David Wasserman, Jan 08 2006

STATUS

approved

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Last modified January 17 18:48 EST 2019. Contains 319251 sequences. (Running on oeis4.)