

A300163


Records in the number of ways to express a number of the form n^2 + 1 as j^2 + k^2 with j > k > 1.


5



1, 2, 3, 5, 7, 8, 11, 15, 17, 23, 31, 35, 39, 47, 63, 71, 95, 127, 143, 161, 191, 215, 255, 287, 319, 383, 575, 639, 767, 959, 1151
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..31.


EXAMPLE

a(6) = 8 because A300162(6) = A300161(6)^2 + 1 = 71825 is the smallest number expressible in 8 ways: 71825 = 265^2 + 40^2 = 260^2 + 65^2 = 257^2 + 76^2 = 247^2 + 104^2 = 236^2 + 127^2 = 215^2 + 160^2 = 208^2 + 169^2 = 191^2 + 188^2.


CROSSREFS

Cf. A060306, A071385, A299707, A299708, A300161, A300162, A300168.
Sequence in context: A191121 A026401 A069353 * A224858 A090704 A112055
Adjacent sequences: A300160 A300161 A300162 * A300164 A300165 A300166


KEYWORD

nonn,more


AUTHOR

Hugo Pfoertner, Feb 27 2018


EXTENSIONS

a(17) from Hugo Pfoertner, Mar 08 2018
a(18)a(21) from Robert Price, Mar 10 2018
a(22)a(31) from Giovanni Resta, Mar 13 2018


STATUS

approved



