A253408 - OEIS

A253408

Values of difference z-y that solve equation x^2 + y^2 = z^2 + 2.

-1, 1, 7, 17, 23, 31, 41, 47, 49, 71, 73, 79, 89, 97, 103, 113, 119, 127, 137, 151, 161, 167, 191, 193, 199, 217, 223, 233, 239, 241, 257, 263, 271, 281, 287, 289, 311, 313, 329, 337, 343, 353, 359, 367, 383, 391, 401, 409, 431, 433, 439, 449, 457, 463, 479, 487

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OFFSET

1,3

COMMENTS

All values are congruent to +-1 (mod 8).

LINKS

Table of n, a(n) for n=1..56.

FORMULA

a(n)^2 mod 8 = 1.

a(n) = A058529(n-1), n>1.

EXAMPLE

a(3)=7 because 25^2 + 41^2 = 48^2 + 2 and 48 - 41 = 7.