The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A257411 Values of n such that there are exactly 4 solutions to x^2 - y^2 = n with x > y >= 0. 4
 96, 105, 120, 135, 160, 165, 168, 189, 195, 216, 224, 231, 255, 256, 264, 273, 280, 285, 297, 312, 345, 351, 352, 357, 375, 385, 399, 408, 416, 420, 429, 435, 440, 455, 456, 459, 465, 483, 512, 513, 520, 540, 544, 552, 555, 561, 595, 608, 609, 615, 616, 621 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Colin Barker, Table of n, a(n) for n = 1..600 EXAMPLE 96 is in the sequence because there are 4 solutions to x^2 - y^2 = 96, namely (x,y) = (10,2), (11,5), (14,10), (25,23). PROG (PARI) is_A257411(n)={A034178(n)==4} \\ M. F. Hasler, Apr 22 2015 CROSSREFS Cf. A257408-A257410, A257412-A257417. Cf. A034178. Sequence in context: A045528 A181470 A306104 * A175116 A153484 A060660 Adjacent sequences:  A257408 A257409 A257410 * A257412 A257413 A257414 KEYWORD nonn AUTHOR Colin Barker, Apr 22 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 7 01:26 EDT 2020. Contains 334836 sequences. (Running on oeis4.)