cp's OEIS Frontend

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.

A226458 G.f.: exp( Sum_{n>=1} A226459(n)*x^n/n ), where A226459(n) = Sum_{d|n} phi(d^d).

Original entry on oeis.org

1, 1, 2, 8, 41, 547, 3193, 104733, 1159483, 29990445, 431859113, 24050995053, 272382000003, 21806033497537, 362394321610042, 15956110448082190, 592910703485329797, 46410258555248498805, 775743319456458483203, 99472768731785230089041
Offset: 0

Views

Author

Paul D. Hanna, Jun 08 2013

Keywords

Examples

			G.f.: A(x) = 1 + x + 2*x^2 + 8*x^3 + 41*x^4 + 547*x^5 + 3193*x^6 +...
where
log(A(x)) = x + 3*x^2/2 + 19*x^3/3 + 131*x^4/4 + 2501*x^5/5 +...+ A226459(n)*x^n/n +...
		

Crossrefs

Programs

  • PARI
    {A226459(n)=sumdiv(n,d, eulerphi(d^d))}
    {a(n)=polcoeff(exp(sum(m=1, n+1, A226459(m)*x^m/m)+x*O(x^n)), n)}
    for(n=0, 30, print1(a(n), ", "))

Formula

The logarithmic derivative yields A226459.