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.

A304113 Restricted growth sequence transform of A278263(n) = A046523(A064413(n)), a filter based on the prime signature of EKG-sequence.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, May 17 2018

Keywords

Comments

For all i, j: a(i) = a(j) => A064742(i) = A064742(j).
For all i, j: a(i) = a(j) => A065203(i) = A065203(j).

Crossrefs

Programs

  • PARI
    \\ Needs also code for A064413:
    write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[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; };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A278263(n) = A046523(A064413(n));
    write_to_bfile(1,rgs_transform(vector(65539,n,A278263(n))),"b304113.txt");

A304112 Restricted growth sequence transform of A246277(A064413(n)), related to indices in the prime factorization of EKG sequence.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, May 17 2018

Keywords

Comments

For all i, j: a(i) = a(j) => A304113(i) = A304113(j).

Crossrefs

Programs

  • PARI
    \\ Needs also code for A064413:
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A246277(n) = { if(1==n, 0, while((n%2), n = A064989(n)); (n/2)); };
    Aux304112(n) = A246277(A064413(n));
    write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[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; };
    write_to_bfile(1,rgs_transform(vector(65539,n,Aux304112(n))),"b304112.txt");

A278264 Least number with the same prime signature as the n-th term in the inverse of EKG-sequence: a(n) = A046523(A064664(n)).

Original entry on oeis.org

1, 2, 2, 2, 6, 4, 6, 8, 6, 4, 12, 2, 12, 2, 2, 2, 6, 12, 2, 12, 6, 2, 2, 16, 24, 8, 6, 6, 6, 2, 2, 2, 6, 32, 4, 30, 2, 36, 2, 24, 6, 6, 16, 2, 6, 30, 2, 12, 12, 6, 6, 2, 36, 48, 2, 4, 6, 24, 2, 12, 6, 60, 6, 64, 24, 2, 128, 6, 12, 6, 6, 12, 30, 30, 6, 2, 30, 30, 2, 72, 12, 2, 96, 6, 60, 48, 6, 2, 2, 2, 6, 6, 6, 24, 6, 6, 30, 12, 96, 6, 24, 6, 2, 6, 2, 12, 6
Offset: 1

Views

Author

Antti Karttunen, Nov 16 2016

Keywords

Comments

This sequence works as a "sentinel" for the inverse of EKG-sequence by matching to any other sequence that is obtained as f(A064664(n)), where f(n) is any function that depends only on the prime signature of n (see the index entry for "sequences computed from exponents in ..."). As of Nov 11 2016 no such sequences were present in the database.
Terms and b-file computed from b-file of A064664 provided by T. D. Noe and Ray Chandler.

Crossrefs

Programs

Formula

a(n) = A046523(A064664(n)).
Showing 1-3 of 3 results.