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.

Showing 1-3 of 3 results.

A286531 Restricted growth sequence of A278531 (prime-signature of A163511).

Original entry on oeis.org

1, 2, 3, 2, 4, 3, 5, 2, 6, 4, 7, 3, 7, 5, 5, 2, 8, 6, 9, 4, 10, 7, 7, 3, 9, 7, 11, 5, 7, 5, 5, 2, 12, 8, 13, 6, 14, 9, 9, 4, 14, 10, 15, 7, 10, 7, 7, 3, 13, 9, 15, 7, 15, 11, 11, 5, 9, 7, 11, 5, 7, 5, 5, 2, 16, 12, 17, 8, 18, 13, 13, 6, 19, 14, 20, 9, 14, 9, 9, 4, 18, 14, 21, 10, 21, 15, 15, 7, 14, 10, 15, 7, 10, 7, 7, 3, 17, 13, 20, 9, 21, 15, 15, 7, 20, 15
Offset: 0

Views

Author

Antti Karttunen, May 17 2017

Keywords

Crossrefs

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 }; \\ Modified from code of M. F. Hasler
    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
    A278222(n) = A046523(A005940(1+n));
    A054429(n) = ((3<<#binary(n\2))-n-1); \\ After M. F. Hasler, Aug 18 2014
    A278531(n) = if(!n,1,A278222(A054429(n)));
    write_to_bfile(0,rgs_transform(vector(65538,n,A278531(n-1))),"b286531.txt");

A285713 a(n) = A046523(A245612(n)).

Original entry on oeis.org

1, 2, 2, 2, 6, 2, 8, 4, 2, 12, 6, 4, 2, 12, 2, 6, 6, 2, 12, 12, 2, 6, 6, 2, 12, 24, 2, 6, 32, 12, 2, 2, 6, 6, 30, 2, 2, 210, 6, 60, 12, 2, 48, 24, 6, 6, 30, 6, 6, 30, 2, 120, 6, 2, 12, 72, 6, 30, 2, 6, 12, 6, 12, 4, 6, 6, 48, 60, 6, 60, 6, 2, 24, 192, 6, 6, 24, 768, 2, 6, 2, 6, 6, 6, 2, 30, 6, 210, 6, 6, 12, 48, 6, 12, 6, 6, 96, 12, 6, 30, 12, 12, 2, 2, 6
Offset: 0

Views

Author

Antti Karttunen, Apr 25 2017

Keywords

Crossrefs

Cf. A305434 (rgs-transform).

Programs

Formula

a(n) = A046523(A245612(n)).
a(n) = A278224(A163511(n)).
a(n) = A286613(A054429(n)). - Antti Karttunen, Jun 01 2018

A305433 Restricted growth sequence transform of ordered pair [A278222(A305295(n)), A278222(A291763(n))], constructed from runlengths of 1-digits and 2-digits in base-3 representation of A245612(n).

Original entry on oeis.org

1, 2, 3, 1, 4, 5, 6, 7, 8, 3, 4, 9, 10, 2, 3, 2, 11, 12, 13, 14, 15, 8, 16, 10, 17, 14, 18, 5, 14, 19, 9, 3, 20, 21, 22, 23, 24, 25, 10, 16, 26, 27, 28, 29, 21, 10, 30, 31, 32, 29, 10, 19, 33, 15, 34, 6, 15, 14, 3, 14, 29, 3, 35, 1, 36, 37, 38, 39, 40, 21, 41, 42, 43, 44, 45, 27, 29, 46, 47, 48, 49, 50, 51, 50, 52, 53, 54, 55, 56, 10, 33, 33, 54, 10, 14
Offset: 0

Views

Author

Antti Karttunen, Jun 01 2018

Keywords

Comments

Restricted growth sequence transform of A290093(A245612(n)).

Crossrefs

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))));
    A289813(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==1, 1, 0)), 2); } \\ From A289813
    A289814(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==2, 1, 0)), 2); } \\ From A289813
    A305295(n) = A289813(A245612(n));
    A291763(n) = A289814(A245612(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));
    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; };
    Aux305433(n) = [A278222(A305295(n)), A278222(A291763(n))];
    v305433 = rgs_transform(vector(65538,n,Aux305433(n-1)));
    A305433(n) = v305433[1+n];
Showing 1-3 of 3 results.