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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A350064 Lexicographically earliest infinite sequence such that a(i) = a(j) => A350062(i) = A350062(j), for all i, j >= 1.

Original entry on oeis.org

1, 2, 3, 3, 4, 3, 5, 3, 6, 4, 7, 3, 8, 3, 6, 6, 9, 3, 10, 3, 11, 6, 12, 3, 11, 6, 6, 6, 13, 6, 14, 3, 6, 6, 11, 5, 15, 3, 16, 6, 17, 3, 18, 3, 6, 19, 20, 3, 19, 4, 16, 3, 21, 3, 22, 3, 16, 11, 23, 3, 24, 6, 6, 11, 11, 6, 25, 6, 6, 3, 26, 6, 27, 6, 6, 6, 19, 6, 28, 3, 16, 6, 29, 11, 30, 16, 31, 19, 32, 11, 33, 6, 30, 30, 30
Offset: 1

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Author

Antti Karttunen, Jan 29 2022

Keywords

Comments

Restricted growth sequence transform of A350062.
For all i, j >= 1: a(i) = a(j) => A324105(i) = A324105(j).
For all i, j >= 2:
a(i) = a(j) => A324119(i) = A324119(j),
a(i) = a(j) => A342655(i) = A342655(j).

Crossrefs

Programs

  • PARI
    up_to = 3000;
    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
    A156552(n) = { my(f = factor(n), p, p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res };
    A350062(n) = if(1==n,0,A046523(A156552(n)));
    v350064 = rgs_transform(vector(up_to, n, A350062(n)));
    A350064(n) = v350064[n];

A350063 a(n) is the smallest number with the same prime signature as A322993(n), with a(1) = 0.

Original entry on oeis.org

0, 1, 1, 2, 1, 2, 1, 2, 2, 4, 1, 2, 1, 2, 2, 6, 1, 2, 1, 2, 4, 6, 1, 2, 2, 6, 2, 6, 1, 6, 1, 2, 2, 6, 2, 8, 1, 2, 6, 6, 1, 2, 1, 2, 2, 24, 1, 2, 2, 4, 6, 2, 1, 2, 4, 2, 6, 12, 1, 2, 1, 6, 2, 12, 2, 6, 1, 6, 2, 2, 1, 6, 1, 6, 2, 6, 2, 6, 1, 2, 6, 6, 1, 12, 6, 30, 24, 24, 1, 12, 4, 6, 12, 60, 6, 6, 1, 4, 6, 6, 1
Offset: 1

Views

Author

Antti Karttunen, Jan 29 2022

Keywords

Crossrefs

Cf. A000265, A046523, A156552, A322993, A350062, A350064, A350065 (rgs-transform).

Programs

  • PARI
    A000265(n) = (n>>valuation(n,2));
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A156552(n) = { my(f = factor(n), p, p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res };
    A350063(n) = if(1==n,0,A046523(A000265(A156552(n))));

Formula

a(1) = 0; for n > 1, a(n) = A046523(A322993(n)) = A046523(A000265(A156552(n))).
Showing 1-2 of 2 results.