A100387 a(n) is the largest number x such that for m=n to n+x-1, A006530(m) decreases.

1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 4, 3, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 3, 2, 1, 4, 3, 2, 1, 2, 1, 3, 2, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 4, 3, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 3, 2, 1, 2, 1, 1, 3, 2, 1, 1, 2, 1, 1, 3, 2, 1, 2, 1, 1, 1, 1, 3, 2, 1, 2, 1, 2, 1, 2, 1, 3, 2, 1

Offset: 2

Author

Labos Elemer, Dec 10 2004

Keywords

• nonn

Comments

A006530(m) is the largest prime factor of m.

Examples

			a(13)=4 because the largest prime factors of 13,14,15,16 are 13,7,5,2; but A006530(17)=17.
		

Crossrefs

Cf. A006530, A070087, A070089, A071870, A079748, A100376, A100385, A100386.

Programs

Mathematica

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Formula

From Pontus von Brömssen, Nov 09 2022: (Start)

a(n) = 1 if and only if n >= 2 and n is a term of A070089.

If a(n) > 1 then a(n) = a(n+1)+1.

(End)

Extensions

Edited by Don Reble, Jun 13 2007