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A126663 Absolute difference between largest prime factors of two successive semiprimes. 3
1, 0, 2, 2, 2, 2, 4, 6, 8, 2, 6, 10, 12, 6, 10, 16, 10, 6, 8, 10, 2, 18, 10, 14, 26, 30, 24, 26, 14, 16, 18, 16, 28, 34, 16, 14, 36, 42, 6, 50, 20, 2, 24, 48, 20, 24, 58, 16, 44, 42, 48, 26, 30, 60, 70, 46, 30, 28, 24, 20, 80, 30, 34, 72, 12, 62, 84, 52, 36, 64, 12, 78, 36, 56, 96 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Absolute first difference of A084127.

LINKS

Table of n, a(n) for n=1..75.

EXAMPLE

a(1) = 1 because 4 = 2*2 and 6 = 2*3 so 3 - 2 = 1;

a(2) = 0 because 6 = 2*3 and 9 = 3*3 so 3 - 3 = 0;

a(3) = 2 because 9 = 3*3 snd 10 = 2*5 so 5 - 3 = 2.

MATHEMATICA

Select[ FactorInteger[ Range[300]], Total[#[[All, 2]]] == 2 &][[All, -1, 1]] // Differences // Abs (* Jean-Fran├žois Alcover, Dec 03 2013 *)

CROSSREFS

Cf. A001358, A006530, A084127.

Sequence in context: A008363 A261611 A097198 * A032600 A103260 A060824

Adjacent sequences:  A126660 A126661 A126662 * A126664 A126665 A126666

KEYWORD

easy,nonn

AUTHOR

Giovanni Teofilatto, Mar 23 2007

EXTENSIONS

Edited and extended by Ray Chandler, Mar 25 2007

STATUS

approved

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Last modified August 20 18:11 EDT 2019. Contains 326154 sequences. (Running on oeis4.)