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 A218029 #10 Aug 11 2015 01:10:41 %S A218029 1,30240,60480,51597803520,687009790646587541893939200, %T A218029 2639216811747930700939756830720000000, %U A218029 399953837788563897626396208106026886244605021117749733129069000654848000000000 %N A218029 Numbers that are equal to the product of the nonzero digits (in base 10) of their square. %e A218029 For n=30240, n^2 = 914,457,600; the product of the nonzero digits of this square, 9*1*4*4*5*7*6 = 30240 = n. %Y A218029 Special case of A218013 where the ratio of the digit-product to the original number is 1. Related to A218072. %K A218029 nonn,base %O A218029 1,2 %A A218029 _Nels Olson_, Oct 18 2012