This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A036744 #30 Jun 28 2023 16:45:50
%S A036744 139854276,152843769,157326849,215384976,245893761,254817369,
%T A036744 326597184,361874529,375468129,382945761,385297641,412739856,
%U A036744 523814769,529874361,537219684,549386721,587432169,589324176,597362481,615387249,627953481,653927184,672935481,697435281,714653289,735982641,743816529,842973156,847159236,923187456
%N A036744 Penholodigital squares: squares containing each of the digits 1..9 exactly once.
%C A036744 Improved Mathematica formula provided. Because the range involved is only from Ceiling[Sqrt[123456789]]=11112 and Floor[Sqrt[987654321]]=31427, it only requires analyzing 20,315 numbers, versus 362,880 permutations of nine digits (as in the current formula). - _Harvey P. Dale_, Apr 17 2002
%C A036744 Since the sum of the digits is 45, the squares are all divisible by 3, so the given Mathematica formula could be sped up by a factor of 3, checking only multiples of 3 rather than all squares. - _Joshua Zucker_, Nov 28 2005
%C A036744 Eight-digit analog gives 5 squares: 13527684, 34857216, 65318724, 73256481, 81432576. - _Zak Seidov_, Mar 01 2011
%F A036744 a(n) = A071519(n)^2.
%p A036744 lim:=floor(sqrt(987654321)): for n from 11112 by 3 to lim do d:=[op(convert(n^2, base, 10))]: pandig:=true: for k from 1 to 9 do if(numboccur(k, d)<>1)then pandig:=false: break: fi: od: if(pandig)then printf("%d, ", n^2): fi: od: # _Nathaniel Johnston_, Jun 22 2011
%t A036744 Select[Range[11112, 31427]^2, Union[Drop[DigitCount[ # ], -1]] == {1} &]
%o A036744 (PARI) A036744 = [n^2 | n <- A071519] \\ or less efficient & more explicit:
%o A036744 A036744 = [n^2 | n <- [1e5\9..1e5\3], vecsort(digits(n^2)) == [1..9]] \\ _M. F. Hasler_, Jun 28 2023
%Y A036744 Cf. A036745, A071519.
%K A036744 nonn,base,fini,full
%O A036744 1,1
%A A036744 _David W. Wilson_
%E A036744 More terms from _Harvey P. Dale_, Sep 26 2001
%E A036744 Keyword base added by _Reinhard Zumkeller_, May 16 2010