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.

Showing 1-3 of 3 results.

A369065 Lexicographically earliest infinite sequence such that a(i) = a(j) => A344026(i) = A344026(j) for all i, j >= 0.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 5, 6, 2, 7, 8, 9, 10, 11, 12, 13, 2, 14, 10, 15, 6, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 2, 27, 19, 13, 9, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 2, 55, 9, 56, 31, 57, 23, 34, 58, 59, 60, 61, 62, 63, 50, 64, 15, 65, 66
Offset: 0

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Author

Antti Karttunen, Jan 16 2024

Keywords

Comments

Restricted growth sequence transform of A344026, i.e., of the arithmetic derivative (A003415) as reordered by the Doudna sequence (A005940).

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; };
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
    A344026(n) = A003415(A005940(1+n));
    v369065 = rgs_transform(vector(1+up_to,n,A344026(n-1)));
    A369065(n) = v369065[1+n];

A369066 Dirichlet convolution of Liouville's lambda (A008836) with A083345, as reordered by the Doudna sequence.

Original entry on oeis.org

0, 1, 1, 0, 1, 3, 1, 3, 1, 5, 6, 0, 1, 2, 0, -1, 1, 7, 8, 0, 10, 14, 5, 8, 1, 2, 3, 0, 2, 0, 4, 6, 1, 11, 12, 0, 14, 20, 7, 14, 16, 34, 44, 0, 7, 9, 0, -3, 1, 2, 3, 0, 5, 5, 2, 5, 2, 6, 8, 0, 2, 7, 1, -3, 1, 13, 14, 0, 16, 32, 11, 20, 18, 54, 68, 0, 11, 13, 0, -5, 22, 76, 92, 0, 124, 92, 34, 36, 11, 13, 20, 0, 16
Offset: 0

Views

Author

Antti Karttunen, Jan 16 2024

Keywords

Crossrefs

Cf. A005940, A008836, A083345, A369067 (rgs-transform), A369069.
Cf. also A366803 (compare the scatter plots).

Programs

Formula

a(n) = A369069(A005940(1+n)).

A369457 Lexicographically earliest infinite sequence such that a(i) = a(j) => A369456(i) = A369456(j) for all i, j >= 0.

Original entry on oeis.org

1, 2, 2, 2, 2, 3, 4, 5, 2, 6, 7, 8, 4, 6, 2, 4, 2, 9, 10, 11, 12, 13, 14, 15, 4, 9, 15, 3, 5, 5, 8, 3, 2, 14, 16, 7, 17, 18, 19, 19, 20, 21, 22, 23, 24, 18, 11, 6, 4, 15, 14, 6, 19, 25, 17, 14, 5, 15, 16, 4, 8, 15, 3, 5, 2, 26, 17, 12, 20, 27, 28, 23, 29, 30, 31, 13, 32, 33, 7, 15, 34, 35, 36, 37, 38, 39, 40, 27, 41, 42, 43, 44, 45, 19
Offset: 0

Views

Author

Antti Karttunen, Jan 27 2024

Keywords

Comments

Restricted growth sequence transform of A369456.

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); };
    A083345(n) = { my(f=factor(n)); numerator(vecsum(vector(#f~, i, f[i, 2]/f[i, 1]))); };
    A369456(n) = A083345(A005940(1+n));
    v369457 = rgs_transform(vector(1+up_to,n,A369456(n-1)));
    A369457(n) = v369457[1+n];
Showing 1-3 of 3 results.