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.

A286614 Restricted growth sequence transform of A286613.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, May 30 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])); }
    A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ This function from Michel Marcus
    A048673(n) = (A003961(n)+1)/2;
    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
    A286613(n) = A046523(A048673(A005940(1+n)));
    write_to_bfile(0,rgs_transform(vector(65537,n,A286613(n-1))),"b286614.txt");

A244154 Permutation of natural numbers: a(0) = 1, a(1) = 2, a(2n) = A254049(a(n)), a(2n+1) = 3*a(n)-1; composition of A048673 and A005940.

Original entry on oeis.org

1, 2, 3, 5, 4, 8, 13, 14, 6, 11, 18, 23, 25, 38, 63, 41, 7, 17, 28, 32, 39, 53, 88, 68, 61, 74, 123, 113, 172, 188, 313, 122, 9, 20, 33, 50, 46, 83, 138, 95, 72, 116, 193, 158, 270, 263, 438, 203, 85, 182, 303, 221, 424, 368, 613, 338, 666, 515, 858, 563, 1201, 938, 1563, 365, 10, 26, 43, 59, 60
Offset: 0

Views

Author

Antti Karttunen, Jun 27 2014

Keywords

Comments

Note the indexing: the domain starts from 0, while the range excludes zero.
From Antti Karttunen, May 30 2017: (Start)
This sequence can be represented as a binary tree. Each left hand child is obtained by applying A254049(n) when the parent contains n, and each right hand child is obtained by applying A016789(n-1) (i.e., multiply by 3, subtract one) to the parent's contents:
1
|
...................2...................
3 5
4......../ \........8 13......../ \........14
/ \ / \ / \ / \
/ \ / \ / \ / \
/ \ / \ / \ / \
6 11 18 23 25 38 63 41
7 17 28 32 39 53 88 68 61 74 123 113 172 188 313 122
etc.
This is a mirror image of the tree depicted in A245612.
(End)

Crossrefs

Programs

Formula

a(n) = A048673(A005940(n+1)).
From Antti Karttunen, May 30 2017: (Start)
a(0) = 1, a(1) = 2, a(2n) = A254049(a(n)), a(2n+1) = 3*a(n)-1.
a(n) = A245612(A054429(n)).
(End)

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
Showing 1-3 of 3 results.