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.

A302795 Restricted growth sequence transform of A278222(A302793(n)).

Original entry on oeis.org

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

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Author

Antti Karttunen, Apr 26 2018

Keywords

Crossrefs

Cf. also A286602, A286622 (compare the scatter-plots).

Programs

  • PARI
    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 }; \\ After code in A005940
    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));
    A193231(n) = { my(x='x); subst(lift(Mod(1, 2)*subst(Pol(binary(n), x), x, 1+x)), x, 2) }; \\ From A193231
    A302793(n) = if(!n,n,A193231(1+A193231(n-1)));
    write_to_bfile(0,rgs_transform(vector(65538,n,A278222(A302793(n-1)))),"b302795.txt");