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.

A372575 Lexicographically earliest infinite sequence such that a(i) = a(j) => A276085(i) = A276085(j), for all i, j >= 1, where A276085 is the primorial base log-function.

Original entry on oeis.org

1, 2, 3, 3, 4, 5, 6, 5, 7, 8, 9, 7, 10, 11, 12, 7, 13, 14, 15, 12, 16, 17, 18, 14, 19, 20, 4, 16, 21, 22, 23, 14, 24, 25, 26, 4, 27, 28, 29, 22, 30, 31, 32, 24, 33, 34, 35, 4, 36, 37, 38, 29, 39, 8, 40, 31, 41, 42, 43, 33, 44, 45, 46, 4, 47, 48, 49, 38, 50, 51, 52, 8, 53, 54, 55, 41, 56, 57, 58, 33, 12, 59, 60, 46, 61, 62, 63, 48, 64, 65, 66, 50, 67, 68, 69, 8
Offset: 1

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Author

Antti Karttunen, May 25 2024

Keywords

Comments

Restricted growth sequence transform of A276085, where A276085 is fully additive with a(p) = A002110(A000720(p)-1).
For all i, j >= 1:
a(i) = a(j) => A035263(i) = A035263(j),
a(i) = a(j) => A369001(i) = A369001(j),
a(i) = a(j) => A372576(i) = A372576(j).
A048103(n) gives the position of the initial occurrence of each n, while A100716 gives the indices of the further occurrences.

Crossrefs

Cf. A048103 (positions of records and initial occurrences), A100716.
Cf. also A322815.

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; };
    A002110(n) = prod(i=1,n,prime(i));
    A276085(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*A002110(primepi(f[k, 1])-1)); };
    v372575 = rgs_transform(vector(up_to, n, A276085(n)));
    A372575(n) = v372575[n];

Formula

For all n >= 1, a(A048103(n)) = n.