Numbers k such that k and k+1 are both antiharmonic numbers (A020487).

Terms

a(0) =49a(1) =324a(2) =1024a(3) =1444a(4) =1681a(5) =2600a(6) =9800a(7) =265225a(8) =332928a(9) =379456a(10) =421200a(11) =1940449a(12) =4198400a(13) =4293184a(14) =4739328a(15) =8346320a(16) =11309768a(17) =27050400a(18) =65918161a(19) =203694425a(20) =384199200a(21) =418488849a(22) =546717924a(23) =2239277041a(24) =2687489280a(25) =4866742025a(26) =5783450400a(27) =6933892900a(28) =7725003664