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.

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

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 * A352204 A224858 A090704

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