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.

A353560 Lexicographically earliest infinite sequence such that a(i) = a(j) => A046523(i) = A046523(j), A001065(i) = A001065(j) and A051953(i) = A051953(j), for all i, j >= 1.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 5, 6, 7, 2, 8, 2, 9, 10, 11, 2, 12, 2, 13, 14, 15, 2, 16, 17, 18, 19, 20, 2, 21, 2, 22, 23, 24, 25, 26, 2, 27, 28, 29, 2, 30, 2, 31, 32, 33, 2, 34, 35, 36, 37, 38, 2, 39, 28, 40, 41, 42, 2, 43, 2, 44, 45, 46, 47, 48, 2, 49, 50, 51, 2, 52, 2, 53, 54, 55, 47, 56, 2, 57, 58, 59, 2, 60, 41, 61, 62, 63, 2, 64, 37
Offset: 1

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Author

Antti Karttunen, Apr 29 2022

Keywords

Comments

Restricted growth sequence transform of the triplet [A046523(n), A001065(n), A051953(n)].
For all i,j:
A305800(i) = A305800(j) => a(i) = a(j),
a(i) = a(j) => A300232(i) = A300232(j), [Combining A046523 and A051953]
a(i) = a(j) => A300235(i) = A300235(j), [Combining A046523 and A001065]
a(i) = a(j) => A305895(i) = A305895(j), [Combining A001065 and A051953]
a(i) = a(j) => A353276(i) = A353276(j). [Needs all three components]

Crossrefs

Differs from A300235 for the first time at n=153, where a(153) = 110, while A300235(153) = 106.
Differs from A305895 for the first time at n=3283, where a(3283) = 2502, while A305895(3283) = 1845.
Differs from A327931 for the first time at n=4433, where a(4433) = 2950, while A327931(4433) = 3393.
Differs from A300249 and from A351260 for the first time at n=105, where a(105) = 75, while A300249(105) = A351260(105) = 56.

Programs

  • PARI
    up_to = 100000;
    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; };
    A001065(n) = (sigma(n)-n);
    A051953(n) = (n-eulerphi(n));
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    Aux353560(n) = [A046523(n), A001065(n), A051953(n)];
    v353560 = rgs_transform(vector(up_to,n,Aux353560(n)));
    A353560(n) = v353560[n];