Define what values of 'n' are impossible to obtain from 3x + 7y = n for positive integers (x,y)

Asked Jul 08 '21 at 17:07

Active Jul 08 '21 at 17:18

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The list I have currently is 1,2,4,5,8,11, which goes for n: 0-20.

I don't quite see a pattern in this. This problem comes from a Stanford Math camp (saw this on Reddit with no answers).

asked Jul 08 '21 at 17:07

Knocker379

Can you give a link to where you saw it on reddit? – coffeemath Jul 08 '21 at 17:15
3

Cf. Frobenius coin problem – J. W. Tanner Jul 08 '21 at 17:16
@J.W.Tanner Note in this question $x,y>0$ unlike the Frobenius problem where $x,y \ge 0.$ – coffeemath Jul 08 '21 at 17:18
This is also a duplicate of Determine the Set of a Sum of Numbers. – robjohn Jul 08 '21 at 18:11

0 Answers0