%I #21 Apr 15 2024 20:35:35
%S 5,15,16,17,45,46,47,48,49,50,51,52,53,54,142,143,144,145,146,147,148,
%T 149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,
%U 166,167,168,169,170,171,172,173,448,449,450,451,452,453,454,455,456
%N Numbers whose square has initial digit '2'.
%H Seiichi Manyama, <a href="/A045856/b045856.txt">Table of n, a(n) for n = 1..10000</a>
%t Select[Range[500],IntegerDigits[#^2][[1]]==2&] (* _Harvey P. Dale_, Apr 15 2024 *)
%o (PARI) isok(n) = digits(n^2)[1] == 2; \\ _Michel Marcus_, May 28 2017
%Y Cf. A045785
%K nonn,base
%O 1,1
%A _Jeff Burch_
%E Corrected by _Seiichi Manyama_, May 28 2017