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 A177887 #17 Nov 07 2017 20:24:30 %S A177887 1,4,5,9,10,14,16,20,25,30,35,36,40,45,49,55,56,64,80,81,84,90,91,100, %T A177887 105,120,121,125,126,140,144,154,160,165,169,180,196,204,220,224,225, %U A177887 231,245,250,256,260,270,285,286,289,315,320,324,336,350,360,361,364,385,390 %N A177887 The areas of Pythagorean triangles divided by 6. %C A177887 Number of terms less than 10^k: 4, 23, 109, 462, 1861, 7255, 27042, 95703, 314534, ..., . %C A177887 This is A009112/6. - _T. D. Noe_, Oct 08 2013 %C A177887 Same as A256418/24, i.e., congrua/24. - _Jonathan Sondow_, Nov 07 2017 %D A177887 Albert H. Beiler, Recreations in the Theory of Numbers, The Queen of Mathematics Entertains, 2nd Ed., Chpt. XIV, "The Eternal Triangle", pp. 104-134, Dover Publ., NY, 1964. %F A177887 A009112(n)/6. %t A177887 (* First run the program given for A009112 *) Union[t/6] %Y A177887 Cf. A009112, A256418. %K A177887 nonn %O A177887 1,2 %A A177887 _Robert G. Wilson v_, Dec 14 2010