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.

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A346237 Dirichlet inverse of A005187.

Original entry on oeis.org

1, -3, -4, 2, -8, 14, -11, 0, 0, 30, -19, -14, -23, 41, 38, 0, -32, -2, -35, -34, 49, 73, -42, 4, 17, 89, 14, -46, -54, -172, -57, 0, 88, 126, 109, 10, -71, 137, 110, 12, -79, -219, -82, -86, -6, 164, -89, 0, 26, -103, 158, -106, -102, -76, 199, 16, 170, 212, -113, 274, -117, 223, 16, 0, 240, -406, -131, -154, 201
Offset: 1

Views

Author

Antti Karttunen, Jul 13 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(dA005187(n) = { my(s=n); while(n>>=1, s+=n); s; };
    v346237 = DirInverseCorrect(vector(up_to,n,A005187(n)));
    A346237(n) = v346237[n];

Formula

a(n) = A346238(n) - A005187(n).

A318446 Inverse Möbius transform of A005187: a(n) = Sum_{d|n} A005187(d).

Original entry on oeis.org

1, 4, 5, 11, 9, 18, 12, 26, 21, 30, 20, 47, 24, 40, 39, 57, 33, 68, 36, 75, 55, 64, 43, 108, 56, 76, 71, 100, 55, 126, 58, 120, 88, 102, 87, 167, 72, 112, 102, 168, 80, 174, 83, 156, 141, 134, 90, 233, 107, 174, 135, 184, 103, 222, 133, 224, 150, 170, 114, 309, 118, 180, 191, 247, 160, 272, 132, 243, 182, 270, 139, 370, 144
Offset: 1

Views

Author

Antti Karttunen, Aug 26 2018

Keywords

Crossrefs

Cf. also A297111, A300244.

Programs

Formula

a(n) = Sum_{d|n} A005187(d).
a(n) = A005187(n) + A318445(n).
a(n) = A318448(n) + A007429(n).

A035532 a(n) = 2*phi(n) if n composite, or 2*phi(n) - (A000120(n)-1) if n prime, where phi = A000010, Euler's totient function, and a(1) = 1.

Original entry on oeis.org

1, 2, 3, 4, 7, 4, 10, 8, 12, 8, 18, 8, 22, 12, 16, 16, 31, 12, 34, 16, 24, 20, 41, 16, 40, 24, 36, 24, 53, 16, 56, 32, 40, 32, 48, 24, 70, 36, 48, 32, 78, 24, 81, 40, 48, 44, 88, 32, 84, 40, 64, 48, 101, 36, 80, 48, 72, 56, 112, 32, 116, 60, 72, 64, 96, 40, 130, 64, 88, 48, 137
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Haskell
    a035532 1 = 1
    a035532 n = if a010051' n == 0 then phi2 else phi2 - a000120 n + 1
                where phi2 = 2 * a000010 n
    -- Reinhard Zumkeller, Feb 04 2015
    
  • Mathematica
    Insert[Table[If[PrimeQ[n],2*EulerPhi[n] - DigitCount[n, 2][[1]] + 1, 2*EulerPhi[n]], {n, 2, 100}], 1, 1] (* Stefan Steinerberger, Apr 11 2006 *)
  • PARI
    A035532(n)=2*eulerphi(n)-if(isprime(n),hammingweight(n)-1,n==1) \\ M. F. Hasler, Mar 10 2018

Formula

a(n) = 2*A000010(n) - A010051(n)*A048881(n-1), for n > 1. - Reinhard Zumkeller, Feb 04 2015, edited by M. F. Hasler, Mar 10 2018
For many values of n, the inverse Möbius transform of this sequence (g.f.: Sum a(n)*x^n/(1-x^n)) equals A005187, but this is not the case for composite n such that A297115(n) <> 0. The equality does hold for A297111 instead. - Antti Karttunen & M. F. Hasler, Mar 10 2018

Extensions

More terms from James Sellers
Definition amended for a(1) = 1 by M. F. Hasler, Mar 10 2018

A378991 Dirichlet inverse of the Möbius transform of A005187, where A005187(n) = 2*n - (number of 1's in binary representation of n).

Original entry on oeis.org

1, -2, -3, 0, -7, 8, -10, 0, -3, 20, -18, -4, -22, 28, 27, 0, -31, 6, -34, -12, 35, 52, -41, 0, 10, 64, 11, -16, -53, -104, -56, 0, 66, 92, 91, 4, -70, 100, 84, 0, -78, -132, -81, -32, 21, 120, -88, 0, 16, -66, 123, -40, -101, -56, 173, 0, 132, 156, -112, 124, -116, 164, 51, 0, 210, -256, -130, -60, 156, -364, -137
Offset: 1

Views

Author

Antti Karttunen, Dec 15 2024

Keywords

Crossrefs

Dirichlet inverse of A297111.
Inverse Möbius transform of A346237.
Cf. A005187.
Cf. also A378989, A378990.

Programs

Formula

a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, dA297111(n/d) * a(d).
a(n) = Sum_{d|n} A346237(d).
Previous Showing 11-14 of 14 results.