login
Prime powers (A025475) representable as (p+q)/2, where p and q are distinct prime powers.
1

%I #6 May 06 2013 01:04:03

%S 25,125,169,243,256,289,625,841,1369,1681,2809,3125,3721,5329,9409,

%T 11881,12769,18769,22201,28561,37249,38809,54289,76729,83521,100489,

%U 113569,151321,160801,196249,201601,208849,292681,323761,375769,390625,410881,426409,452929,502681

%N Prime powers (A025475) representable as (p+q)/2, where p and q are distinct prime powers.

%e a(1) = 25 = (1 + 49) / 2.

%e a(2) = 125 = (81 + 169) / 2.

%e a(3) = 169 = (49 + 289) / 2.

%e a(4) = 243 = (125 + 361) / 2.

%e a(5) = 256 = (169 + 343) / 2.

%e a(6) = 289 = (49 + 529) / 2.

%Y Cf. A025475, A225389.

%K nonn

%O 1,1

%A _Alex Ratushnyak_, May 05 2013