A057369 Numbers k that can be expressed as k = w+x = y*z with w*x = (y+z)^2 where w, x, y, and z are all positive integers.

16, 18, 25, 45, 50, 80, 234, 250, 261, 425, 1025, 1040, 1530, 1625, 1746, 2320, 4250, 7605, 7794, 9650, 10413, 11050, 11925, 14416, 23425, 24050, 27920, 71298, 75650, 78416, 81693, 129625, 151625, 200720, 221425, 257085, 264618, 338949, 340245, 416050, 488610

Offset: 1

Author

Naohiro Nomoto, Sep 23 2000

Keywords

• nonn

Examples

			a(1) = 16 = 8+8 = 4*4; 8*8 = (4+4)^2.
		

Links

• Soumyadeep Dhar, Table of n, a(n) for n = 1..112

Crossrefs

Cf. A057370, A057371, A057372, A057373, A057442.

Programs

PARI

is(k) = fordiv(k, y, if(issquare(k^2 - 4*(y+k/y)^2), return(1))); 0; \\ Jinyuan Wang, May 01 2021

Extensions

More terms from Jinyuan Wang, May 01 2021