A124809 Numbers of the form (square + 1) that are not squarefree.

50, 325, 1025, 1445, 1682, 1850, 3250, 4625, 4901, 6725, 8650, 9802, 11450, 13690, 13925, 17425, 20450, 24650, 28225, 33125, 37250, 42850, 47525, 53825, 57122, 59050, 63002, 66050, 71825, 79525, 85850, 94250, 101125, 106930, 110225, 117650

Offset

1,1

Comments

The sequence is infinite (see comment in A049532). - Emmanuel Vantieghem, Oct 25 2016

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

a(n) = A049532(n)^2 + 1.

Mathematica

Select[Range[400]^2+1, !SquareFreeQ[#]&] (* Harvey P. Dale, Sep 15 2016 *)

Prog

(Magma) [n^2+1: n in [1..500]| not IsSquarefree(n^2+1)]; // Vincenzo Librandi, Oct 26 2016
(PARI) is(n)=issquare(n-1) && !issquarefree(n) \\ Charles R Greathouse IV, Nov 05 2017

Crossrefs

Cf. A002522, A013929, A049532, A069987.

Sequence in context: A183698 A183690 A221572 * A261803 A184564 A184556

Adjacent sequences: A124806 A124807 A124808 * A124810 A124811 A124812

Keyword

nonn

Author

Reinhard Zumkeller, Nov 08 2006

Status

approved