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 1-8 of 8 results.

A378755 Dirichlet convolution of A033879 and A346248.

Original entry on oeis.org

1, 0, 1, 2, 1, 2, 3, 10, 11, 2, 1, 14, 3, 6, 7, 42, 1, 26, 3, 14, 17, 2, 5, 70, 15, 6, 81, 34, 1, 22, 5, 170, 7, 2, 17, 146, 3, 6, 17, 70, 1, 54, 3, 14, 69, 10, 5, 326, 55, 34, 7, 34, 5, 234, 7, 162, 17, 2, 1, 138, 5, 10, 155, 682, 17, 22, 3, 14, 27, 54, 1, 730, 5, 6, 89, 34, 17, 54, 3, 326, 571, 2, 5, 318, 7, 6, 7
Offset: 1

Views

Author

Antti Karttunen, Dec 11 2024

Keywords

Crossrefs

Cf. A033879, A346248, A378754 (Dirichlet inverse).

Programs

Formula

a(n) = Sum_{d|n} A033879(d)*A346248(n/d).

A346246 Dirichlet inverse of A344587, 2*A003961(n) - sigma(A003961(n)).

Original entry on oeis.org

1, -2, -4, -1, -6, 10, -10, -2, -3, 14, -12, 4, -16, 22, 26, -4, -18, 2, -22, 6, 42, 26, -28, 6, -5, 34, -6, 10, -30, -66, -36, -8, 50, 38, 62, 7, -40, 46, 66, 10, -42, -106, -46, 12, 14, 58, -52, 8, -9, 2, 74, 16, -58, -2, 74, 18, 90, 62, -60, -18, -66, 74, 26, -16, 98, -126, -70, 18, 114, -150, -72, 18, -78, 82, 12, 22
Offset: 1

Views

Author

Antti Karttunen, Jul 19 2021

Keywords

Comments

Dirichlet inverse of the deficiency of prime shifted n.

Crossrefs

Cf. A000203, A003961, A003973, A323910, A344587, A346247, A346251 (positions of zeros).
Cf. also A346235, A346248, A346254.

Programs

  • PARI
    up_to = 16384;
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961
    A344587(n) = { my(u=A003961(n)); (u+u - sigma(u)); };
    v346246 = DirInverseCorrect(vector(up_to,n,A344587(n)));
    A346246(n) = v346246[n];

Formula

a(n) = A323910(A003961(n)).
a(n) = A346247(n) - A344587(n).

A346250 Sum of -A252748 and its Dirichlet inverse.

Original entry on oeis.org

2, 0, 0, 1, 0, 2, 0, -3, 1, 6, 0, -11, 0, 6, 6, -17, 0, -23, 0, -17, 6, 18, 0, -39, 9, 18, -15, -25, 0, -48, 0, -51, 18, 30, 18, -49, 0, 30, 18, -77, 0, -72, 0, -35, -61, 34, 0, -85, 9, -31, 30, -43, 0, -123, 54, -97, 30, 54, 0, -117, 0, 50, -77, -89, 54, -96, 0, -53, 34, -104, 0, -19, 0, 66, -55, -61, 54, -120, 0
Offset: 1

Views

Author

Antti Karttunen, Jul 19 2021

Keywords

Crossrefs

Programs

  • PARI
    up_to = 16384;
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961
    A252748(n) = (A003961(n) - (2*n));
    v346248 = DirInverseCorrect(vector(up_to,n,-A252748(n)));
    A346248(n) = v346248[n];
    A346250(n) = (A346248(n)-A252748(n));

Formula

a(n) = A346248(n) - A252748(n).

A346235 Dirichlet inverse of A341530, gcd(n*sigma(A003961(n)), sigma(n)*A003961(n)).

Original entry on oeis.org

1, -1, -2, 0, -2, -32, -4, -4, 3, 2, -2, 34, -2, -16, -112, 8, -2, 125, -4, 0, 8, 0, -6, -128, 3, -14, -8, -124, -2, 8, -2, -10, -4, 2, -320, 920, -2, -4, 4, 8, -2, 64, -4, -358, 430, -12, -6, 528, -3, -5, -352, 16, -6, -368, -48, 224, 0, 2, -2, 104, -2, -12, -12, 28, -4, 16, -4, 0, -36, 400, -2, -440, -2, -2, 450, 8, -248, 128
Offset: 1

Views

Author

Antti Karttunen, Jul 11 2021

Keywords

Crossrefs

Programs

  • PARI
    up_to = 65537;
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961
    A341530(n) = { my(t=A003961(n), s=sigma(t)); gcd((n*s), sigma(n)*t); };
    v346235 = DirInverseCorrect(vector(up_to,n,A341530(n)));
    A346235(n) = v346235[n];

A346254 Dirichlet inverse of A336849.

Original entry on oeis.org

1, -3, -5, 0, -7, 25, -11, 0, 0, 21, -13, -30, -17, 55, 35, 0, -19, -100, -23, 0, 55, 39, -29, 36, 0, 85, 0, -66, -31, -175, -37, 0, 65, 57, 77, 400, -41, 115, 85, 0, -43, -495, -47, 108, 0, 145, -53, -216, 0, 98, 171, -68, -59, 500, 169, 0, 115, 93, -61, 210, -67, 111, 0, 0, 119, -325, -71, 0, 261, -385, -73, -120, -79, 205, 0, -138
Offset: 1

Views

Author

Antti Karttunen, Jul 19 2021

Keywords

Crossrefs

Cf. A000203, A003961, A003973, A336849, A346255, A346256 (positions of zeros).
Cf. also A346235, A346246, A346248.

Programs

  • PARI
    up_to = 16384;
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961
    A336849(n) = { my(u=A003961(n)); (u/gcd(u, sigma(u))); };
    v346254 = DirInverseCorrect(vector(up_to,n,A336849(n)));
    A346254(n) = v346254[n];

Formula

a(n) = A346255(n) - A336849(n).

A346477 Dirichlet inverse of A346476.

Original entry on oeis.org

1, -1, -1, 2, -3, 5, -3, 2, 8, 13, -9, -2, -9, 17, 11, 8, -15, -8, -15, -12, 19, 37, -17, 18, 8, 41, -4, -12, -27, -33, -25, 20, 37, 61, 25, 56, -33, 65, 35, 38, -39, -45, -39, -42, -36, 77, -41, 32, 32, -20, 53, -42, -47, 96, 35, 58, 61, 109, -57, 132, -55, 109, -48, 56, 43, -121, -63, -72, 71, -109, -69, 56
Offset: 1

Views

Author

Antti Karttunen, Jul 29 2021

Keywords

Crossrefs

Programs

  • PARI
    up_to = 16384;
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA346476(n) = (n+n-A250469(n));
    v346477 = DirInverseCorrect(vector(up_to,n,A346476(n)));
    A346477(n) = v346477[n];

Formula

a(1) = 1; and for n > 2, a(n) = -Sum_{d|n, dA346476(n/d).
a(n) = A346478(n) - A346476(n).
a(p) = A252748(p) = A346248(p) = -A346476(p) = -A062234(A000720(p)), for any prime p.

A347098 a(1) = 1; a(n) = -Sum_{d|n, d < n} A336853(n/d) * a(d), where A336853(n) = A003961(n) - n.

Original entry on oeis.org

1, -1, -2, -4, -2, -5, -4, -10, -12, -7, -2, -1, -4, -11, -12, -16, -2, -1, -4, -7, -18, -13, -6, 42, -20, -17, -42, -5, -2, 21, -6, -4, -24, -19, -26, 106, -4, -23, -30, 38, -2, 45, -4, -25, -10, -29, -6, 196, -56, -17, -36, -23, -6, 123, -28, 82, -42, -31, -2, 225, -6, -37, 4, 80, -38, 15, -4, -43, -52, 39, -2, 413
Offset: 1

Views

Author

Antti Karttunen, Aug 19 2021

Keywords

Comments

Dirichlet inverse of the pointwise sum of A336853 and A063524 (1, 0, 0, 0, ...).

Crossrefs

Programs

  • Mathematica
    f[p_, e_] := NextPrime[p]^e; s[1] = 0; s[n_] := Times @@ f @@@ FactorInteger[n] - n; a[1] = 1; a[n_] := a[n] = -DivisorSum[n, a[#] * s[n/#] &, # < n &]; Array[a, 100] (* Amiram Eldar, Nov 27 2021 *)
  • PARI
    up_to = 16384;
    A336853(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); (factorback(f)-n); };
    Aux347098(n) = if(1==n,n,A336853(n));
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA347098(n) = v347098[n];

Formula

a(1) = 1; and for n > 1, a(n) = -Sum_{d|n, d < n} A336853(n/d) * a(d).
For all n >= 1, a(A000040(n)) = -A001223(n).

A376404 Dirichlet inverse of 2*phi(n) - phi(A003961(n)), where phi is Euler totient function and A003961(n) is fully multiplicative function with a(prime(i)) = prime(i+1).

Original entry on oeis.org

1, 0, 0, 2, -2, 4, -2, 10, 8, 4, -8, 16, -8, 8, 8, 42, -14, 28, -14, 12, 16, 4, -16, 72, 6, 8, 64, 28, -26, 16, -24, 170, 8, 4, 20, 144, -32, 8, 16, 52, -38, 40, -38, 0, 40, 12, -40, 328, 30, 28, 8, 16, -46, 228, 24, 124, 16, 4, -56, 112, -54, 12, 96, 682, 32, -8, -62, -12, 24, 24, -68, 712, -66, 8, 56, 4, 32, 16
Offset: 1

Views

Author

Antti Karttunen, Nov 15 2024

Keywords

Crossrefs

Dirichlet inverse of -A349754, inverse Möbius transform of A346248.
Cf. also A323912.

Programs

  • PARI
    A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
    A349754(n) = (eulerphi(A003961(n))-2*eulerphi(n));
    memoA376404 = Map();
    A376404(n) = if(1==n,1,my(v); if(mapisdefined(memoA376404,n,&v), v, v = -sumdiv(n,d,if(dA349754(n/d)*A376404(d),0)); mapput(memoA376404,n,v); (v)));

Formula

a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, dA349754(n/d) * a(d).
a(n) = Sum_{d|n} A346248(d).
Showing 1-8 of 8 results.