A066566 - OEIS

%I #24 Dec 05 2024 18:57:57

%S 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,40,41,42,43,44,45,

%T 46,47,48,49,90,91,92,93,94,95,96,97,98,99,150,151,152,153,154,155,

%U 156,157,158,159,230,231,232,233,234,235,236,237,238,239,330,331,332,333

%N Numbers that when decremented by the sum of their digits produce a square.

%C The squares in this sequence are divisible by 9.

%H Indranil Ghosh, <a href="/A066566/b066566.txt">Table of n, a(n) for n = 1..11130</a> (terms 1..1000 from Harry J. Smith)

%e 155 is a member as 155 - 1 - 5 - 5 = 144 = 12^2.

%t Select[Range[0,350],IntegerQ[Sqrt[#-Total[IntegerDigits[#]]]]&]  (* _Harvey P. Dale_, Feb 24 2011 *)

%o (PARI) isok(k)={issquare(k-sumdigits(k))}

%Y Cf. A066564.

%K base,nonn

%O 1,3

%A _Amarnath Murthy_, Dec 18 2001

%E More terms from _Jason Earls_, Dec 20 2001

%E Offset changed from 0 to 1 by _Harry J. Smith_, Mar 05 2010