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 1-5 of 5 results.

A344768 a(n) = n - A344767(n); Möbius transform of A344765.

Original entry on oeis.org

0, 0, 2, 0, 2, 7, 2, 0, 3, 12, 2, 11, 2, 15, 15, 0, 2, 19, 2, 13, 22, 23, 2, 25, 5, 28, 9, 32, 2, 19, 2, 0, 33, 36, 30, 41, 2, 39, 40, 48, 2, 28, 2, 27, 47, 47, 2, 47, 7, 50, 51, 29, 2, 53, 58, 23, 58, 60, 2, 72, 2, 63, 48, 0, 55, 66, 2, 72, 69, 63, 2, 24, 2, 76, 76, 43, 71, 77, 2, 47, 27, 84, 2, 57, 70, 87, 87, 96, 2, 73
Offset: 1

Views

Author

Antti Karttunen, May 30 2021

Keywords

Crossrefs

Programs

Formula

a(n) = n - A344767(n) = n - Sum_{d|n} A008683(n/d) * A011772(d).
a(n) = Sum_{d|n} A008683(n/d) * A344765(d).

A345055 Dirichlet inverse of A011772.

Original entry on oeis.org

1, -3, -2, 2, -4, 9, -6, 0, -4, 20, -10, -16, -12, 29, 11, 0, -16, 16, -18, -43, 18, 49, -22, 18, -8, 60, -2, -43, -28, -89, -30, 0, 29, 80, 34, 1, -36, 89, 36, 71, -40, -136, -42, -96, 27, 109, -46, -18, -12, 8, 47, -123, -52, -19, 70, -25, 54, 140, -58, 326, -60, 149, 21, 0, 71, -201, -66, -128, 65, -264, -70, -140, -72, 180, 16
Offset: 1

Views

Author

Antti Karttunen, Jun 20 2021

Keywords

Crossrefs

Cf. A011772, A345053 (positions of zeros), A345065.
Cf. also A344767.

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(dA011772(n) = { if(n==1, return(1)); my(f=factor(if(n%2, n, 2*n)), step=vecmax(vector(#f~, i, f[i, 1]^f[i, 2]))); forstep(m=step, 2*n, step, if(m*(m-1)/2%n==0, return(m-1)); if(m*(m+1)/2%n==0, return(m))); }; \\ From A011772
    v345055 = DirInverseCorrect(vector(up_to,n,A011772(n)));
    A345055(n) = v345055[n];
    (Python 3.8+)
    from itertools import combinations
    from math import prod
    from sympy import factorint, divisors
    from sympy.ntheory.modular import crt
    def A011772(n):
        plist = [p**q for p, q in factorint(2*n).items()]
        return 2*n-1 if len(plist) == 1 else min(min(crt([m,2*n//m],[0,-1])[0],crt([2*n//m,m],[0,-1])[0]) for m in (prod(d) for l in range(1,len(plist)//2+1) for d in combinations(plist,l)))
    def A345055(n): return 1 if n == 1 else -sum(A011772(n//d)*A345055(d) for d in divisors(n, generator=True) if d < n) # Chai Wah Wu, Jun 20 2021

Formula

a(2^i) = 0 for i >= 3. See A345053. - Chai Wah Wu, Jul 05 2021

A346614 Inverse Moebius transform of A011772.

Original entry on oeis.org

1, 4, 3, 11, 5, 9, 7, 26, 11, 12, 11, 24, 13, 17, 12, 57, 17, 25, 19, 34, 15, 25, 23, 54, 29, 28, 37, 31, 29, 37, 31, 120, 24, 36, 25, 48, 37, 41, 27, 64, 41, 48, 43, 64, 29, 49, 47, 117, 55, 60, 36, 74, 53, 78, 25, 94, 39, 60, 59, 82, 61, 65, 50, 247, 42, 52, 67, 59, 48
Offset: 1

Views

Author

N. J. A. Sloane, Aug 18 2021

Keywords

Crossrefs

A346615 Moebius transform of A344005.

Original entry on oeis.org

1, 0, 1, 2, 3, 0, 5, 4, 6, 0, 9, -1, 11, 0, 0, 8, 15, 0, 17, -2, -1, 0, 21, 1, 20, 0, 18, -1, 27, 0, 29, 16, 0, 0, 5, -1, 35, 0, -1, 7, 39, 0, 41, -1, -2, 0, 45, -1, 42, 0, 0, -2, 51, 0, -3, -4, -1, 0, 57, 11, 59, 0, 15, 32, 10, 0, 65, -2, 0, 0, 69, -5, 71, 0, -1, -1, 6, 0, 77, -8
Offset: 0

Views

Author

N. J. A. Sloane, Aug 18 2021

Keywords

Crossrefs

Programs

  • PARI
    f(n) = my(m=1); while ((m*(m+1))%n, m++); m; \\ A344005
    a(n) = sumdiv(n, d, moebius(n/d)*f(d)); \\ Michel Marcus, Aug 19 2021

A346616 Inverse Moebius transform of A344005.

Original entry on oeis.org

1, 2, 3, 5, 5, 6, 7, 12, 11, 10, 11, 12, 13, 14, 12, 27, 17, 22, 19, 17, 15, 22, 23, 27, 29, 26, 37, 24, 29, 24, 31, 58, 24, 34, 25, 36, 37, 38, 27, 39, 41, 30, 43, 36, 29, 46, 47, 57, 55, 58, 36, 41, 53, 74, 25, 38, 39, 58, 59, 49, 61, 62, 50, 121, 42, 48, 67, 53, 48, 50, 71, 59
Offset: 1

Views

Author

N. J. A. Sloane, Aug 18 2021

Keywords

Crossrefs

Showing 1-5 of 5 results.