cp's OEIS Frontend

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.

A061867 Squares whose product of digits is also a square (allowing zeros).

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%I A061867 #11 Oct 03 2014 14:12:45
%S A061867 0,1,4,9,49,100,144,289,400,441,900,1024,1089,1444,1600,2025,2209,
%T A061867 2304,2401,2500,2601,2704,2809,3025,3600,4096,4900,5041,6084,6400,
%U A061867 7056,7744,8100,9025,9409,9604,9801,10000,10201,10404,10609,10816,11025,11236
%N A061867 Squares whose product of digits is also a square (allowing zeros).
%D A061867 Felice Russo, A set of new Smarandache Functions, Sequences and conjectures in number theory, pp-64, American Research Press, Lupton USA.
%D A061867 Amarnath Murthy, Exploring some new ideas on Smarandache Type Sets, Functions and sequences, Vol. 11, No. 1-2-3, Spring 2000.
%D A061867 Amarnath Murthy, On the infinitude of Smarandache multiplicative square sequence, (to be published in Smarandache Notions Journal).
%F A061867 a(n) ~ n^2. - _Charles R Greathouse IV_, Sep 19 2012
%t A061867 Select[Range[0,200]^2,IntegerQ[Sqrt[Times@@IntegerDigits[#]]]&] (* _Harvey P. Dale_, Oct 03 2014 *)
%o A061867 (PARI) isok(n) = {if (! issquare(n), return (0)); digs = digits(n, 10); issquare(prod(i=1, #digs, digs[i]));}  \\ _Michel Marcus_, Aug 02 2013
%Y A061867 Sequence A053059 removes the numbers with zeros.
%K A061867 base,easy,nonn
%O A061867 1,3
%A A061867 Larry Reeves (larryr(AT)acm.org), May 11 2001