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.

A349444 Dirichlet convolution of A003602 (Kimberling's paraphrases) with A092673 (Dirichlet inverse of A001511).

Original entry on oeis.org

1, -1, 1, 0, 2, -1, 3, 0, 3, -2, 5, 0, 6, -3, 4, 0, 8, -3, 9, 0, 6, -5, 11, 0, 10, -6, 9, 0, 14, -4, 15, 0, 10, -8, 12, 0, 18, -9, 12, 0, 20, -6, 21, 0, 12, -11, 23, 0, 21, -10, 16, 0, 26, -9, 20, 0, 18, -14, 29, 0, 30, -15, 18, 0, 24, -10, 33, 0, 22, -12, 35, 0, 36, -18, 20, 0, 30, -12, 39, 0, 27, -20, 41, 0, 32
Offset: 1

Views

Author

Antti Karttunen, Nov 18 2021

Keywords

Crossrefs

Cf. A001511, A003602, A008683, A092673, A349445 (Dirichlet inverse), A349446 (sum with it).
Cf. also A349431, A349447.

Programs

  • Mathematica
    s[n_] := MoebiusMu[n] - If[OddQ[n], 0, MoebiusMu[n/2]]; k[n_] := (n/2^IntegerExponent[n, 2] + 1)/2; a[n_] := DivisorSum[n, s[#]*k[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 19 2021 *)
  • PARI
    A003602(n) = (1+(n>>valuation(n,2)))/2;
    A092673(n) = if(n<1, 0, moebius(n) - if( n%2, 0, moebius(n/2))); \\ From A092673
    A349444(n) = sumdiv(n,d,A003602(n/d)*A092673(d));

Formula

a(n) = Sum_{d|n} A003602(n/d) * A092673(d).

A349445 Dirichlet convolution of A001511 (the 2-adic valuation of 2n) with A349134 (the Dirichlet inverse of Kimberling's paraphrases).

Original entry on oeis.org

1, 1, -1, 1, -2, -1, -3, 1, -2, -2, -5, -1, -6, -3, 0, 1, -8, -2, -9, -2, 0, -5, -11, -1, -6, -6, -4, -3, -14, 0, -15, 1, 0, -8, 0, -2, -18, -9, 0, -2, -20, 0, -21, -5, 2, -11, -23, -1, -12, -6, 0, -6, -26, -4, 0, -3, 0, -14, -29, 0, -30, -15, 3, 1, 0, 0, -33, -8, 0, 0, -35, -2, -36, -18, 4, -9, 0, 0, -39, -2, -8
Offset: 1

Views

Author

Antti Karttunen, Nov 18 2021

Keywords

Crossrefs

Cf. A001511, A003602, A349134, A349444 (Dirichlet inverse), A349446 (sum with it).
Cf. also A349432, A349448.

Programs

  • Mathematica
    k[n_] := (n / 2^IntegerExponent[n, 2] + 1)/2; kinv[1] = 1; kinv[n_] := kinv[n] = -DivisorSum[n, kinv[#]*k[n/#] &, # < n &]; a[n_] := DivisorSum[n, IntegerExponent[2*#, 2]*kinv[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 19 2021 *)
  • PARI
    A001511(n) = (1+valuation(n,2));
    A003602(n) = (1+(n>>valuation(n,2)))/2;
    memoA349134 = Map();
    A349134(n) = if(1==n,1,my(v); if(mapisdefined(memoA349134,n,&v), v, v = -sumdiv(n,d,if(dA003602(n/d)*A349134(d),0)); mapput(memoA349134,n,v); (v)));
    A349445(n) = sumdiv(n,d,A001511(n/d)*A349134(d));

Formula

a(n) = Sum_{d|n} A001511(n/d) * A349134(d).
If p odd prime, a(p) = (1-p)/2. - Bernard Schott, Nov 19 2021

A349433 a(n) = A349431(n) + A349432(n).

Original entry on oeis.org

2, 0, 0, 1, 0, 2, 0, 3, 1, 4, 0, 3, 0, 6, 4, 7, 0, 3, 0, 6, 6, 10, 0, 5, 4, 12, 3, 9, 0, -4, 0, 15, 10, 16, 12, 5, 0, 18, 12, 10, 0, -6, 0, 15, 2, 22, 0, 9, 9, 8, 16, 18, 0, 5, 20, 15, 18, 28, 0, -4, 0, 30, 3, 31, 24, -10, 0, 24, 22, -12, 0, 9, 0, 36, 0, 27, 30, -12, 0, 18, 7, 40, 0, -6, 32, 42, 28, 25, 0, -6, 36, 33
Offset: 1

Views

Author

Antti Karttunen, Nov 17 2021

Keywords

Crossrefs

Cf. also A349446.

Programs

  • Mathematica
    k[n_] := (n / 2^IntegerExponent[n, 2] + 1)/2; kinv[1] = 1; kinv[n_] := kinv[n] = -DivisorSum[n, kinv[#] * k[n/#] &, # < n &]; a[n_] := DivisorSum[n, # * kinv[n/#] + # * MoebiusMu[#] * k[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 18 2021 *)
  • PARI
    A349433(n) = (A349431(n) + A349432(n)); \\ Needs also code from A349431 and A349432.

Formula

a(1) = 2, and for n >1, a(n) = -Sum_{d|n, 1A349431(d) * A349432(n/d). [As the sequences are Dirichlet inverses of each other]
Showing 1-3 of 3 results.