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.

A303779 Restricted growth sequence transform of A278222(A303775(n)).

Original entry on oeis.org

1, 2, 3, 2, 3, 2, 4, 5, 6, 5, 3, 2, 7, 4, 7, 4, 6, 2, 4, 7, 4, 8, 4, 9, 10, 7, 11, 7, 3, 2, 11, 7, 4, 12, 13, 7, 4, 6, 5, 3, 8, 7, 11, 7, 14, 15, 8, 5, 4, 10, 8, 4, 12, 7, 8, 7, 8, 7, 13, 9, 15, 9, 13, 9, 13, 2, 16, 9, 4, 13, 9, 4, 17, 9, 4, 13, 7, 18, 13, 7, 4, 13, 9, 19, 15, 8, 4, 17, 9, 8, 7, 8, 9, 13, 15, 13, 7, 11, 7, 3, 11, 7, 12, 13, 7
Offset: 0

Views

Author

Antti Karttunen, May 06 2018

Keywords

Crossrefs

Programs

  • PARI
    \\ Needs also code from A303775:
    rgs_transform(invec) = { my(occurrences = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(occurrences,invec[i]), my(pp = mapget(occurrences, invec[i])); outvec[i] = outvec[pp] , mapput(occurrences,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])); }
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A278222(n) = A046523(A005940(1+n));
    write_to_bfile(0,rgs_transform(vector(65538,n,A278222(A303775(n-1)))),"b303779.txt");

Formula

For all i, j: a(i) = a(j) => A303780(i) = A303780(j).