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 A066565 #16 Dec 08 2024 23:51:41 %S A066565 1,2,3,4,5,6,7,8,9,18,45,49,96,98,100,135,144,200,250,288,289,300,338, %T A066565 378,384,400,405,441,500,600,700,800,882,900,1444,1445,1575,1715,1800, %U A066565 2205,2209,2744,2809,3703,4418,4500,4900,5290,6144,6912,6962,7560,7623 %N A066565 Numbers that when multiplied by the product of their nonzero digits produce a square. %H A066565 Harry J. Smith, <a href="/A066565/b066565.txt">Table of n, a(n) for n = 1..1000</a> %e A066565 45 is a member as 45*4*5 = 900 = 30^2; 135 is a member as 135*3*5 = 2025 = 45^2; 200 is a member as 200*2 = 400. %o A066565 (PARI) isok(k) = issquare( k * vecprod(select(x->(x!=0), digits(k))) ) %Y A066565 Cf. A051801. %K A066565 base,nonn %O A066565 1,2 %A A066565 _Amarnath Murthy_, Dec 18 2001 %E A066565 More terms from _Jason Earls_, Dec 24 2001 %E A066565 Offset changed from 0 to 1 by _Harry J. Smith_, Mar 04 2010