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A175180 Numbers n such that n^2 + 2 is powerful in the sense of A001694. 1
5, 265, 13775, 716035, 9980583, 37220045 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This sequence is infinite (F. Lucas).

The n^2 are a subset of A076445, so 23 terms of the sequence are known from there. - R. J. Mathar, Mar 05 2010

Together with 1, supersequence of A238799. - Arkadiusz Wesolowski, Mar 06 2014

REFERENCES

J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 265, pp 71, Ellipses, Paris 2008.

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

5 is in the sequence because 5^2 + 2 = 1^2 * 3^3 is powerful.

265 is in the sequence because 265^2 + 2 = 51^2*3^3 is powerful.

13775 is in the sequence because 13775^2 + 2 = 2651^2 * 3^3 is powerful.

PROG

(PARI) is(n)=ispowerful(n^2+2) \\ Charles R Greathouse IV, Feb 04 2013

CROSSREFS

Cf. A001694, A238799.

Sequence in context: A079681 A086656 A034602 * A238799 A113257 A180820

Adjacent sequences:  A175177 A175178 A175179 * A175181 A175182 A175183

KEYWORD

nonn

AUTHOR

Michel Lagneau, Mar 01 2010

EXTENSIONS

Examples rephrased by R. J. Mathar, Feb 24 2010, Mar 05 2010

STATUS

approved

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Last modified January 19 12:36 EST 2020. Contains 331049 sequences. (Running on oeis4.)