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.

A305434 Restricted growth sequence transform of A285713, formed from the prime signature of A245612(n).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jun 01 2018

Keywords

Crossrefs

Cf. also A305433.

Programs

  • PARI
    A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ From A003961
    A048673(n) = (A003961(n)+1)/2;
    A254049(n) = A048673((2*n)-1);
    A245612(n) = if(n<2,1+n,if(!(n%2),(3*A245612(n/2))-1,A254049(A245612((n-1)/2))));
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A285713(n) = A046523(A245612(n));
    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; };
    v305434 = rgs_transform(vector(65538,n,A285713(n-1)));
    A305434(n) = v305434[1+n];