A057369 - OEIS

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

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OFFSET

1,1

LINKS

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

EXAMPLE

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

PROG

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

CROSSREFS

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

Sequence in context: A337374 A255847 A160778 * A178110 A117100 A101848