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 A264810 #7 Mar 14 2018 06:01:01 %S A264810 1,2,2,3,3,4,4,5,5,6,6,7,7,7,7,8,8,9,9,10,10,11,11,12,12,12,12,13,13, %T A264810 14,14,15,15,15,15,16,16,16,16,17,17,18,18,19,19,20,20,21,21,21,21,22, %U A264810 22,23,23,24,24,25,25,26,26,26,26,27,27,28,28,28,28 %N A264810 Number of numbers k <= n such that phi(m) = k for some m. %C A264810 Partial sums of A264739; %C A264810 a(n) = n - A180639(n). %H A264810 Reinhard Zumkeller, <a href="/A264810/b264810.txt">Table of n, a(n) for n = 1..10000</a> %o A264810 (Haskell) %o A264810 a264810 n = a264810_list !! (n-1) %o A264810 a264810_list = scanl1 (+) a264739_list %o A264810 (PARI) first(n)=my(s); vector(n,k,s+=istotient(k)) \\ _Charles R Greathouse IV_, Sep 02 2015 %Y A264810 Cf. A000010, A002202, A264739. %K A264810 nonn %O A264810 1,2 %A A264810 _Reinhard Zumkeller_, Nov 26 2015