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.

A344594 Lexicographically earliest infinite sequence such that a(i) = a(j) => A342920(i) = A342920(j), for all i, j >= 1.

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 3, 4, 2, 1, 5, 1, 2, 6, 7, 1, 8, 1, 5, 6, 2, 1, 9, 10, 2, 7, 5, 1, 11, 1, 12, 6, 2, 13, 14, 1, 2, 6, 15, 1, 8, 1, 5, 16, 2, 1, 17, 18, 19, 6, 5, 1, 20, 21, 3, 6, 2, 1, 22, 1, 2, 23, 24, 25, 4, 1, 5, 6, 26, 1, 27, 1, 2, 28, 5, 29, 4, 1, 30, 31, 2, 1, 14, 32, 2, 6, 3, 1, 33, 34, 5, 6, 2, 35, 36, 1, 37, 38, 39, 1, 4, 1, 3, 40
Offset: 1

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Author

Antti Karttunen, May 26 2021

Keywords

Comments

Restricted growth sequence transform of A342920, where A342920(n) = A342002(A108951(n)) = A329047(n) / A344592(n).

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; };
    A034386(n) = prod(i=1, primepi(n), prime(i));
    A108951(n) = { my(f=factor(n)); prod(i=1, #f~, A034386(f[i, 1])^f[i, 2]) };  \\ From A108951
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A003557(n) = (n/factorback(factorint(n)[, 1]));
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A342002(n) = { my(u=A276086(n)); (A003415(u) / A003557(u)); };
    A342920(n) = A342002(A108951(n));
    v344594 = rgs_transform(vector(up_to, n, A342920(n)));
    A344594(n) = v344594[n];