A087238 First differences of A057809.

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

Offset: 2

Author

Labos Elemer, Sep 04 2003

Keywords

• nonn

Examples

			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).
		

Links

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

Crossrefs

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

Programs

Mathematica

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

Formula

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