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.

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A318836 Product_{d|n, dA007431(d) > 0} prime(A007431(d)), where A007431 is the Möbius transform of Euler's totient function.

Original entry on oeis.org

1, 2, 2, 2, 2, 4, 2, 4, 4, 10, 2, 8, 2, 22, 20, 12, 2, 28, 2, 20, 44, 46, 2, 48, 10, 62, 28, 44, 2, 100, 2, 84, 92, 94, 110, 112, 2, 118, 124, 300, 2, 484, 2, 92, 700, 146, 2, 1008, 22, 530, 188, 124, 2, 1036, 230, 1452, 236, 206, 2, 2000, 2, 218, 3388, 1596, 310, 2116, 2, 188, 292, 5170, 2, 7056, 2, 298, 5300, 236, 506
Offset: 1

Views

Author

Antti Karttunen, Sep 05 2018

Keywords

Crossrefs

Cf. A007431, A062790, A318837 (rgs-transform).
Cf. also A318838.

Programs

  • PARI
    A007431(n) = sumdiv(n,d,moebius(n/d)*eulerphi(d));
    A318836(n) = { my(m=1); fordiv(n,d,if((dA007431(d)!=0),m *= prime(A007431(d)))); (m); };

Formula

a(n) = product_{d|n, dA008578(1+A007431(d)).
For all n >= 1, A056239(a(n)) = A062790(n).

A318839 Restricted growth sequence transform of A318838.

Original entry on oeis.org

1, 1, 2, 2, 3, 2, 4, 5, 6, 3, 7, 8, 9, 4, 10, 11, 12, 6, 13, 10, 14, 7, 15, 16, 17, 9, 18, 14, 19, 10, 20, 21, 22, 12, 23, 24, 25, 13, 26, 27, 28, 14, 29, 22, 30, 15, 31, 32, 33, 17, 34, 26, 35, 18, 36, 37, 38, 19, 39, 40, 41, 20, 42, 43, 44, 22, 45, 34, 46, 23, 47, 48, 49, 25, 50, 38, 51, 26, 52, 53, 54, 28, 55, 56, 57, 29, 58, 59, 60, 30, 61, 46, 62, 31, 63
Offset: 1

Views

Author

Antti Karttunen, Sep 05 2018

Keywords

Comments

For all i, j: a(i) = a(j) => A000010(i) = A000010(j).

Crossrefs

Cf. also A318837.

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A007431(n) = sumdiv(n,d,moebius(n/d)*eulerphi(d));
    A318838(n) = { my(m=1); fordiv(n,d,if((A007431(d)!=0),m *= prime(A007431(d)))); (m); };
    v318839 = rgs_transform(vector(up_to,n,A318838(n)));
    A318839(n) = v318839[n];
Showing 1-2 of 2 results.