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A087238 First differences of A057809. 1
2, 2, 2, 19, 3, 3, 63, 4, 20, 210, 5, 5, 10, 5, 5, 648, 72, 12, 24, 6, 6, 6, 1925, 7, 7, 7, 7, 7, 5314, 16, 16, 16, 8, 8, 15054, 9, 765, 40240, 40, 30, 10, 30, 40, 10, 10, 10, 110477, 305655, 12, 144, 12, 12, 12, 12, 12, 12, 12, 204, 60, 12, 36, 12, 12, 12, 12, 823046, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Giovanni Resta, Table of n, a(n) for n = 2..1161

FORMULA

a(n)=A057809(n+1)-A057809(n)

EXAMPLE

Large differences arise between max term in a cluster and least one in the next cluster of A057809. While small entries obtained as differences inside a cluster.

E.g.:...,21,6467079011,198,22,110,132,22,242,66,17541629593,23,... shows by first differences the transition from the 21st cluster to 23rd solution-set over the 22nd-set with multiples of 22.

First cluster is empty, while 11th contains one term (see A038227).

MATHEMATICA

Differences[Select[Range[2, 1500000], Divisible[#, PrimePi[#]]&]] (* Harvey P. Dale, Aug 13 2012 *)

CROSSREFS

Cf. A038623-A038627, A057809, A087235-A087242.

Sequence in context: A214756 A079007 A064215 * A226935 A099640 A140283

Adjacent sequences:  A087235 A087236 A087237 * A087239 A087240 A087241

KEYWORD

nonn

AUTHOR

Labos Elemer, Sep 04 2003

STATUS

approved

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Last modified December 12 15:11 EST 2019. Contains 329960 sequences. (Running on oeis4.)