

A300167


Numbers n such that n^2+1 can be expressed as j^2+k^2, j>k>1, gcd(j,k)=1, in more ways than for any smaller n.


4




OFFSET

1,1


LINKS

Table of n, a(n) for n=1..10.


EXAMPLE

a(1)= 8 because 8^2 + 1 = A300168(1) = 65 = 7^2 + 4^2.
a(2) = 47 because it is the smallest n leading to more than 1 way of expressing n^2+1 : 47^2 + 1 = 2010 = 43^2 + 19^2 = 41^2 + 23^2 = 37^2 + 29^2.
a(3) = 242 because 242^2 + 1 = 58565 is the smallest number that can be expressed in more than 3 ways:
58565 = 241^2 + 22^2 = 239^2 + 38^2 = 223^2 + 94^2 = 214^2 + 113^2 = 209^2 + 122^2 = 206^2 + 127^2 = 193^2 + 146^2.


CROSSREFS

Cf. A300161, A300165, A300168.
Sequence in context: A081279 A099110 A106393 * A029760 A139262 A026900
Adjacent sequences: A300164 A300165 A300166 * A300168 A300169 A300170


KEYWORD

nonn,hard,more


AUTHOR

Hugo Pfoertner, Feb 27 2018


EXTENSIONS

a(7) from Robert Price, Mar 11 2018
a(7) corrected, a(8)a(9) added by Ray Chandler, Dec 23 2019
a(10) added by Ray Chandler, Dec 31 2019


STATUS

approved



