A130638 - OEIS

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A130638

a(n) = 1 iff d(n) = d(n+1), otherwise a(n)=0; where d(n) is the number of divisors of natural number.

0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,1`
	LINKS	`Table of n, a(n) for n=1..80.` `Index entries for characteristic functions`
	MATHEMATICA	`Table[If[Length[Divisors[n]] == Length[Divisors[n + 1]], 1, 0], {n, 1, 80}] - Stefan Steinerberger, Aug 12 2007`
	CROSSREFS	`Sequence in context: A084928 A033683 A216284 * A030217 A030215 A098108` `Adjacent sequences: A130635 A130636 A130637 * A130639 A130640 A130641`
	KEYWORD	`nonn`
	AUTHOR	`Giovanni Teofilatto, Aug 11 2007`
	EXTENSIONS	`Corrected and extended by Stefan Steinerberger, Aug 12 2007`
	STATUS	`approved`

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Last modified May 21 12:46 EDT 2013. Contains 225486 sequences.