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 A069557 #26 May 05 2024 19:59:59
%S A069557 1,4,9,25,49,64,81,324,361,625,961,4624,8649,7354944
%N A069557 Squares in which the k-th significant digit either divides k or is a multiple of k. Is 1 only in case k has no other single-digit divisor.
%C A069557 If the smallest prime divisor of n is > 7 only in such case the n-th digit is 1.
%C A069557 a(15) > 10^25 if it exists. - _David A. Corneth_, May 05 2024
%C A069557 The definition implies that no digit can be zero. - _N. J. A. Sloane_, May 05 2024
%H A069557 David A. Corneth, <a href="/A069557/a069557.gp.txt">PARI program</a>
%e A069557 8649 is a member in which the fourth digit is 8, a multiple of 4, the third one is 6, a multiple of 3, the second one is 4, a multiple of 2 and the least significant digit is 9.
%t A069557 okQ[n_]:=Module[{idn=IntegerDigits[n]}, Count[idn,0]==0 && And@@Divisible[idn,Range[Length[idn],1,-1]]]; Select[Range[500]^2, okQ] (* _Harvey P. Dale_, Dec 20 2010 *)
%o A069557 (PARI) \\ See PARI link
%Y A069557 Cf. A052041, A069556, A069560.
%K A069557 base,hard,more,nonn
%O A069557 1,2
%A A069557 _Amarnath Murthy_, Mar 22 2002
%E A069557 More terms from _Sascha Kurz_, Mar 23 2002
%E A069557 Offset corrected and a(14) from _Sean A. Irvine_, May 04 2024