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.

A327930 Product_{d|n, d>1} prime(A003415(d)), where A003415(x) gives the arithmetic derivative of x.

Original entry on oeis.org

1, 2, 2, 14, 2, 44, 2, 518, 26, 68, 2, 16324, 2, 92, 76, 67858, 2, 41756, 2, 42364, 116, 164, 2, 116569684, 58, 188, 2678, 84364, 2, 3609848, 2, 27753922, 172, 268, 148, 4353104756, 2, 292, 212, 528236716, 2, 10506584, 2, 256004, 164996, 388, 2, 9360895334252, 86, 388484, 284, 346108, 2, 1802063692, 212, 1495183172, 316
Offset: 1

Views

Author

Antti Karttunen, Sep 30 2019

Keywords

Crossrefs

Programs

  • PARI
    A003415(n) = {my(fac); if(n<1, 0, fac=factor(n); sum(i=1, matsize(fac)[1], n*fac[i, 2]/fac[i, 1]))}; \\ From A003415
    A327930(n) = { my(m=1); fordiv(n,d,if((d>1), m *= prime(A003415(d)))); (m); };

Formula

a(n) = Product_{d|n, d>1} A000040(A003415(d)).
For all n >= 2, a(n) = prime(A003415(n)) * A064989(A319356(n)).
A001221(a(n)) = A319685(n).
A001222(a(n)) = A032741(n).
A007814(a(n)) = A001221(n).
A056239(a(n)) = A319684(n).