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.

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A335421 Lexicographically earliest infinite sequence such that a(i) = a(j) => A046523(A335422(i)) = A046523(A335422(j)) for all i, j >= 0.

Original entry on oeis.org

1, 1, 1, 2, 1, 3, 2, 3, 1, 4, 3, 5, 2, 6, 3, 7, 1, 8, 4, 9, 3, 10, 5, 5, 2, 10, 6, 5, 3, 8, 7, 5, 1, 11, 8, 12, 4, 13, 9, 14, 3, 15, 10, 16, 5, 10, 5, 17, 2, 15, 10, 16, 6, 10, 5, 10, 3, 18, 8, 19, 7, 3, 5, 5, 1, 20, 11, 20, 8, 21, 12, 22, 4, 22, 13, 23, 9, 8, 14, 20, 3, 22, 15, 22, 10, 24, 16, 25, 5, 26, 10, 14, 5, 20, 17, 27, 2, 22, 15, 23, 10, 10, 16, 28, 6, 26
Offset: 0

Views

Author

Antti Karttunen, Jun 09 2020

Keywords

Comments

For all i, j: A324400(i) = A324400(j) => a(i) = a(j) => A335420(i) = A335420(j).

Crossrefs

Programs

  • PARI
    up_to = 65537;
    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; };
    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
    A054429(n) = ((3<<#binary(n\2))-n-1); \\ From A054429
    A163511(n) = if(!n,1,A005940(1+A054429(n)))
    A335422(n) = A005940(1+A163511(n));
    v335421 = rgs_transform(vector(1+up_to,n,A046523(A335422(n-1))));
    A335421(n) = v335421[1+n];

Formula

For all n >= 0, a(2^n) = 1.

A335422 a(n) = A005940(1+A163511(n)).

Original entry on oeis.org

2, 3, 5, 4, 7, 10, 9, 6, 11, 36, 21, 50, 25, 16, 15, 8, 13, 154, 225, 486, 55, 84, 147, 98, 49, 90, 81, 28, 35, 30, 27, 12, 17, 2500, 429, 8918, 1225, 1080, 9375, 840, 91, 2662, 495, 3750, 605, 220, 363, 1250, 121, 88, 525, 240, 625, 490, 99, 126, 77, 64, 105, 72, 125, 22, 45, 18, 19, 26950, 21609, 43350, 1105, 186340, 67881
Offset: 0

Views

Author

Antti Karttunen, Jun 09 2020

Keywords

Comments

Permutation of natural numbers larger than one.

Crossrefs

Programs

Formula

a(n) = A005940(1+A163511(n)).
For all n >= 0, a(2^n) = A000040(2+n).
A001222(a(n)) = A335420(n).
Showing 1-2 of 2 results.