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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 n, A000005. 0
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

Cf. A000005.

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 August 20 03:34 EDT 2017. Contains 290823 sequences.