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 A147591 #6 Sep 02 2017 20:05:03 %S A147591 1,2,3,4,5,6,7,8,9,11,17,22,33,44,55,66,71,77,88,99,111,115,151,157, %T A147591 175,222,333,444,511,517,555,571,666,715,751,777,888,999,1111,1135, %U A147591 1153,1177,1315,1339,1351,1393,1513,1531,1557,1575,1717,1755,1771,1933,2000 %N A147591 RootMeanSquare(digits of n) is an integer. %H A147591 Harvey P. Dale, <a href="/A147591/b147591.txt">Table of n, a(n) for n = 1..1000</a> %e A147591 n=1236, RMS(digits of 1351)=sqrt((1^2+3^2+5^2+1^2)/4)=sqrt(36/4)=sqrt(9)=3. %t A147591 Select[Range[2000],IntegerQ[RootMeanSquare[IntegerDigits[#]]]&] (* _Harvey P. Dale_, Sep 02 2017 *) %Y A147591 Cf. A140480 %K A147591 base,easy,nonn %O A147591 1,2 %A A147591 _Ctibor O. Zizka_, Nov 08 2008