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 A064649 #14 Mar 06 2016 16:59:31 %S A064649 1,4,12,40,140,816,5082,40800,363258,3632880,39916910,479052528, %T A064649 6227020956,87178936992,1307674429440,20922800222848,355687428096272, %U A064649 6402373892575992,121645100408832342,2432902011892837920 %N A064649 Row sums of the table A047916. %H A064649 Harry J. Smith, <a href="/A064649/b064649.txt">Table of n, a(n) for n=1..100</a> %F A064649 a(n) = Sum_{d|n} phi(n/d)*(n/d)^d*d!. - _Michel Marcus_, Mar 06 2016 %p A064649 A064649 := proc(n) local d, s; s := 0; for d in divisors(n) do s := s + phi(n/d)*(n/d)^d*d!; od; RETURN(s); end; %t A064649 a[n_] := DivisorSum[n, EulerPhi[n/#]*(n/#)^#*#!&]; Array[a, 20] (* _Jean-François Alcover_, Mar 06 2016 *) %o A064649 (PARI) { for (n=1, 100, a=0; v=divisors(n); for (i=1, length(v), d=v[i]; a+=eulerphi(n/d)*(n/d)^d*d!); write("b064649.txt", n, " ", a) ) } \\ _Harry J. Smith_, Sep 21 2009 %o A064649 (PARI) a(n) = sumdiv(n, d, eulerphi(n/d)*(n/d)^d*d!); \\ _Michel Marcus_, Mar 06 2016 %o A064649 (Haskell) %o A064649 a064649 = sum . a047916_row -- _Reinhard Zumkeller_, Mar 19 2014 %Y A064649 Also n*A061417[n]. Cf. A047918, A002619. %K A064649 nonn %O A064649 1,2 %A A064649 _Antti Karttunen_, Oct 04 2001