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 1-4 of 4 results.

A318834 a(n) = Product_{d|n, dA019565(phi(d)), where phi is the Euler totient function A000010.

Original entry on oeis.org

1, 2, 2, 4, 2, 12, 2, 12, 6, 20, 2, 108, 2, 60, 30, 60, 2, 540, 2, 300, 90, 84, 2, 2700, 10, 140, 90, 2700, 2, 6300, 2, 420, 126, 44, 150, 121500, 2, 132, 210, 10500, 2, 283500, 2, 5292, 3150, 660, 2, 132300, 30, 5500, 66, 14700, 2, 267300, 210, 472500, 198, 1540, 2, 4630500, 2, 4620, 47250, 4620, 350, 873180, 2, 1452, 990
Offset: 1

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Author

Antti Karttunen, Sep 04 2018

Keywords

Crossrefs

Cf. A000010, A019565, A318835 (rgs-transform).
Cf. also A293214, A293231, A300834.

Programs

  • PARI
    A019565(n) = {my(j,v); factorback(Mat(vector(if(n, #n=vecextract(binary(n), "-1..1")), j, [prime(j), n[j]])~))}; \\ From A019565
    A318834(n) = { my(m=1); fordiv(n,d,if(d < n,m *= A019565(eulerphi(d)))); m; };

Formula

a(n) = Product_{d|n, dA019565(A000010(d)).
A048675(a(n)) = A051953(n).

A318831 Restricted growth sequence transform of A278222(A000010(n)).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 3, 1, 2, 2, 1, 1, 1, 2, 3, 1, 2, 3, 4, 1, 3, 2, 3, 2, 5, 1, 6, 1, 3, 1, 2, 2, 3, 3, 2, 1, 3, 2, 7, 3, 2, 4, 8, 1, 7, 3, 1, 2, 4, 3, 3, 2, 3, 5, 8, 1, 6, 6, 3, 1, 2, 3, 3, 1, 4, 2, 4, 2, 3, 3, 3, 3, 6, 2, 8, 1, 9, 3, 7, 2, 1, 7, 5, 3, 4, 2, 3, 4, 6, 8, 3, 1, 2, 7, 6, 3, 4, 1, 9, 2, 2
Offset: 1

Views

Author

Antti Karttunen, Sep 04 2018

Keywords

Comments

Sequence allots a distinct value for each distinct multiset formed from the lengths of 1-runs in the binary expansion of A000010(n).
For all i, j: a(i) = a(j) => A295660(i) = A295660(j).

Crossrefs

Compare also with the scatterplots of A286622, A304101 and A318832.

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 };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A278222(n) = A046523(A005940(1+n));
    v318831 = rgs_transform(vector(up_to,n,A278222(eulerphi(n))));
    A318831(n) = v318831[n];

A332826 Lexicographically earliest infinite sequence such that a(i) = a(j) => A046523(A332824(i)) = A046523(A332824(j)) for all i, j.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Feb 25 2020

Keywords

Crossrefs

Cf. A019434 (positions of 3's).
Cf. also A318835.

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; };
    A019565(n) = {my(j,v); factorback(Mat(vector(if(n, #n=vecextract(binary(n), "-1..1")), j, [prime(j), n[j]])~))}; \\ From A019565
    A332824(n) = { my(m=1); fordiv(n,d,m *= A019565(eulerphi(d))); (m); };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    v332826 = rgs_transform(vector(up_to,n,A046523(A332824(n))));
    A332826(n) = v332826[n];

A353565 Lexicographically earliest infinite sequence such that a(i) = a(j) => A353564(i) = A353564(j), where A353564(n) = Product_{d|n, dA276086(phi(d)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Apr 27 2022

Keywords

Comments

Restricted growth sequence transform of A353564.
For all i, j: A305800(i) = A305800(j) => a(i) = a(j) => A051953(i) = A051953(j).

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; };
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A353564(n) = { my(m=1); fordiv(n,d,if(d < n,m *= A276086(eulerphi(d)))); m; };
    v353565 = rgs_transform(vector(up_to,n,A353564(n)));
    A353565(n) = v353565[n];
Showing 1-4 of 4 results.