This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A179114 G.f.: A(x) = exp( Sum_{n>=1} A179115(n)*x^n/n ), where A179115(n) = Sum_{d|n} phi(d^tau(d)). 1
 1, 1, 2, 4, 13, 19, 103, 131, 515, 777, 2183, 3387, 92950, 98220, 215084, 407878, 1321714, 1941644, 10099460, 13008998, 49257496, 74663830, 209907775, 326405877, 5955260642, 6463849558, 14769440215, 27326857279, 88012522809 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS phi(n) = A000010(n) is the Euler totient function of n. tau(n) = A000005(n) is the number of divisors of n. LINKS EXAMPLE G.f.: A(x) = 1 + x + 2*x^2 + 4*x^3 + 13*x^4 + 19*x^5 + 103*x^6 +... log(A(x)) = x + 3*x^2/2 + 7*x^3/3 + 35*x^4/4 + 21*x^5/5 + 441*x^6/6 +... PROG (PARI) {a(n)=polcoeff(exp(sum(m=1, n, sumdiv(m, d, eulerphi(d^sigma(d, 0)))*x^m/m)+x*O(x^n)), n)} CROSSREFS Cf. A179115, A000010 (phi), A000005 (tau). Sequence in context: A240096 A018761 A276118 * A082015 A018263 A018587 Adjacent sequences:  A179111 A179112 A179113 * A179115 A179116 A179117 KEYWORD nonn AUTHOR Paul D. Hanna, Jul 10 2010 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 22 18:53 EDT 2019. Contains 323481 sequences. (Running on oeis4.)