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A290340 Numbers n such that each of the four consecutive integers n, n+1, n+2, n+3 have squarefree rank 1. 2
17, 241, 242, 1249, 4049, 4799, 17297, 120049, 206081, 281249, 388961, 470447, 538721, 1462049, 1566449, 1808801, 1916881, 3302449, 3302450, 3693761, 3959297, 5385761, 5664976, 6118001, 6986321, 9305297, 10479041, 14268481 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A162642(k) is the squarefree rank of k.

LINKS

Jason Kimberley, Table of n, a(n) for n = 1..79

PROG

(MAGMA)

A162642:=func<n|&+[Integers()|pe[2]mod 2:pe in Factorisation(n)]>;

c:=func<a|[n:n in a|n+1 in a]>;

c(c(c([n:n in[1..10^6]|A162642(n)eq 1])));

CROSSREFS

Cf. A162642, A229125, A277225.

Sequence in context: A264455 A142126 A251769 * A103772 A196987 A051560

Adjacent sequences:  A290337 A290338 A290339 * A290341 A290342 A290343

KEYWORD

nonn

AUTHOR

Jason Kimberley, Jul 27 2017

STATUS

approved

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Last modified January 21 08:09 EST 2020. Contains 331104 sequences. (Running on oeis4.)