A338195 Numbers k such that 3/k = 1/x + 1/y has a solution with 0 < x < y < k.

18, 20, 35, 36, 40, 45, 54, 56, 60, 70, 72, 77, 80, 84, 90, 100, 104, 105, 108, 110, 112, 120, 126, 135, 140, 143, 144, 154, 160, 162, 168, 170, 175, 176, 180, 182, 189, 198, 200, 208, 209, 210, 216, 220, 221, 224, 225, 231, 234, 240, 245, 252, 260, 264, 266, 270

Offset: 1

Author

Rainer Rosenthal and Hugo Pfoertner, Oct 15 2020

Keywords

• nonn

Crossrefs

Cf. A073101, A337432.

Cf. A004611 (Numbers n such that 3/n cannot be written as the sum of 2 unit fractions).

Programs

PARI

for(k=3,270, forstep(y=k-1,1,-1,my(x=3/k-1/y); if(numerator(x)==1&&1/x