A240974 - OEIS

%I #92 Jul 22 2024 15:25:36

%S 0,2,3,8,15,18,22,24,35,48,52,63,69,80,99,110,114,120,143,168,195,198,

%T 224,228,240,255,288,322,323,360,399,440,483,488,494,528,575,605,624,

%U 675,702,711,728,783,840,899,960,970,1004,1023,1088,1155,1224,1272,1295,1298,1368,1443

%N Numbers of the form x^y - x*y for x > 1 and y > 1.

%C Primes of the form a(k)-1: 2, 7, 17, 23, 47, 79, 109, 167, 197, 223, 239, 359, 439, 487, 701, 727, 839, 1087, 1223, 1297, 1367, ...

%C Numbers that occur in more than one way include 4^n - 4*n = 2^(2*n) - 2*(2*n).  Are those all?  - _Robert Israel_, Jul 21 2024

%H Robert Israel, <a href="/A240974/b240974.txt">Table of n, a(n) for n = 1..10000</a>

%e 0 is in this sequence because 2^2 - 2*2 = 0 for x = 2 > 1 and y = 2 > 1.

%p N:= 10000: # for terms <= N

%p R:= {}:

%p for y from 2 while 2^y - 2*y <= N do

%p   for x from 2 do

%p     v:= x^y - x*y;

%p     if v > N then break fi;

%p     R:= R union {v};

%p od od:

%p sort(convert(R,list)); # _Robert Israel_, Jul 21 2024

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Sep 13 2014