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.

A340142 Dirichlet inverse of A160595, where A160595(x) = phi(x)/gcd(phi(x), x-1).

Original entry on oeis.org

1, -1, -1, -1, -1, 0, -1, -1, -2, -2, -1, 1, -1, -4, -2, -1, -1, 1, -1, 1, -1, -8, -1, 2, -4, -10, -4, 9, -1, 6, -1, -1, -3, -14, -10, 3, -1, -16, -10, 4, -1, 4, -1, 1, 5, -20, -1, 3, -6, -5, -14, 17, -1, 4, -18, -10, -7, -26, -1, 8, -1, -28, -9, -1, -1, 24, -1, 1, -9, 30, -1, 4, -1, -34, -5, 25, -13, 22, -1, 7, -8, -38, -1, -5
Offset: 1

Views

Author

Antti Karttunen, Dec 29 2020

Keywords

Crossrefs

Cf. A160595.
Cf. also A340141, A340143.

Programs

  • PARI
    up_to = 65537;
    A160595(n) = { my(x=eulerphi(n)); x/gcd(x,n-1); };
    DirInverse(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = -sumdiv(n, d, if(dA160595(n)));
    A340142(n) = v340142[n];

A340141 Numerators of the sequence whose Dirichlet convolution with itself yields sequence A160595(x) = phi(x)/gcd(phi(x), x-1).

Original entry on oeis.org

1, 1, 1, 7, 1, 3, 1, 25, 11, 7, 1, 19, 1, 11, 7, 363, 1, 31, 1, 43, 5, 19, 1, 63, 19, 23, 61, 3, 1, 15, 1, 1335, 9, 31, 23, 189, 1, 35, 23, 139, 1, 29, 1, 115, 23, 43, 1, 867, 27, 127, 31, 11, 1, 163, 39, 279, 17, 55, 1, 73, 1, 59, 123, 9923, 5, -15, 1, 187, 21, -9, 1, 615, 1, 71, 127, 19, 29, 47, 1, 1875, 1363, 79, 1, 203, 31
Offset: 1

Views

Author

Antti Karttunen, Dec 29 2020

Keywords

Crossrefs

Cf. A046644 (denominators).
Cf. A160595.
Cf. also A340142, A340143.

Programs

  • PARI
    up_to = 65537;
    A160595(n) = { my(x=eulerphi(n)); x/gcd(x,n-1); };
    DirSqrt(v) = {my(n=#v, u=vector(n)); u[1]=1; for(n=2, n, u[n]=(v[n]/v[1] - sumdiv(n, d, if(d>1&&dA160595(n)));
    A340141(n) = numerator(v340141rat[n]);

A340146 Möbius transform of A247074(x) = phi(x)/(Product_{primes p dividing x} gcd(p-1, x-1)).

Original entry on oeis.org

1, 0, 0, 1, 0, 1, 0, 2, 2, 3, 0, 1, 0, 5, 1, 4, 0, 2, 0, 3, 2, 9, 0, 2, 4, 11, 6, -3, 0, 2, 0, 8, 4, 15, 5, 4, 0, 17, 5, 6, 0, 3, 0, 9, -1, 21, 0, 4, 6, 12, 7, -5, 0, 6, 9, 18, 8, 27, 0, 3, 0, 29, 4, 16, 2, -11, 0, 15, 10, -6, 0, 8, 0, 35, 4, -7, 14, 6, 0, 12, 18, 39, 0, 13, 3, 41, 13, 18, 0, 13, 1, 21, 14, 45, 17, 8
Offset: 1

Views

Author

Antti Karttunen, Dec 29 2020

Keywords

Crossrefs

Programs

  • PARI
    A247074(n) = { my(f=factor(n)); eulerphi(f)/prod(i=1, #f~, gcd(f[i, 1]-1, n-1)); }; \\ From A247074
    A340146(n) = sumdiv(n,d,moebius(n/d)*A247074(d));

Formula

a(n) = Sum_{d|n} A008683(n/d) * A247074(d).

A340190 Möbius transform of A063994(x) = Product_{primes p dividing x} gcd(p-1, x-1).

Original entry on oeis.org

1, 0, 1, 0, 3, -1, 5, 0, 0, -3, 9, 0, 11, -5, -1, 0, 15, 0, 17, 0, -3, -9, 21, 0, 0, -11, 0, 2, 27, 1, 29, 0, -7, -15, -5, 0, 35, -17, -9, 0, 39, 3, 41, 0, 4, -21, 45, 0, 0, 0, -13, 2, 51, 0, -9, -2, -15, -27, 57, 0, 59, -29, 0, 0, 1, 11, 65, 0, -19, 7, 69, 0, 71, -35, 0, 2, -11, 9, 77, 0, 0, -39, 81, -2, -3, -41, -25
Offset: 1

Views

Author

Antti Karttunen, Dec 31 2020

Keywords

Crossrefs

Programs

  • PARI
    A063994(n) = { my(f=factor(n)); prod(i=1, #f~, gcd(f[i, 1]-1, n-1)); };
    A340190(n) = sumdiv(n,d,moebius(n/d)*A063994(d));

Formula

a(n) = Sum_{d|n} A008683(n/d) * A063994(d).
a(n) = A063994(n) - A340191(n).
Showing 1-4 of 4 results.