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.

A296085 Filter sequence combining A296078(n) and A296092(n), the prime signatures of 1+phi(n) and 1+sigma(n).

Original entry on oeis.org

1, 2, 1, 3, 1, 1, 2, 4, 5, 1, 1, 1, 5, 2, 6, 7, 1, 8, 5, 9, 5, 1, 2, 9, 10, 1, 1, 5, 1, 9, 5, 11, 12, 5, 6, 13, 5, 1, 14, 5, 1, 1, 13, 15, 9, 1, 2, 3, 5, 15, 16, 17, 5, 2, 1, 6, 4, 5, 1, 2, 13, 1, 18, 19, 14, 15, 5, 16, 20, 14, 1, 21, 13, 5, 3, 5, 1, 6, 4, 15, 15, 1, 5, 21, 16, 5, 12, 1, 5, 14, 1, 22, 5, 5, 2, 15, 13, 13, 1, 5, 1, 15, 18, 9, 9
Offset: 1

Views

Author

Antti Karttunen, Dec 08 2017

Keywords

Comments

Restricted growth sequence transform of P(A296078(n), A296092(n)), where P(a,b) is a two-argument form of A000027 used as a Cantor pairing function N x N -> N.
For all i, j:
a(i) = a(j) => A296213(i) = A296213(j).

Crossrefs

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; };
    write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ This function from Charles R Greathouse IV, Aug 17 2011
    A296078(n) = A046523(1+eulerphi(n));
    A296092(n) = A046523(1+sigma(n));
    Anotsubmitted5(n) = (1/2)*(2 + ((A296078(n)+A296092(n))^2) - A296078(n) - 3*A296092(n));
    write_to_bfile(1,rgs_transform(vector(up_to,n,Anotsubmitted5(n))),"b296085.txt");