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.

A300822 Möbius transform of A300222.

Original entry on oeis.org

0, 2, 0, -2, 2, 4, 6, 8, 0, -4, 2, -4, 0, -6, 4, -2, 8, 12, 18, 22, 12, 14, 20, 16, 22, 24, 0, 0, 2, -8, 0, -4, 4, -4, 0, -12, 0, -18, 0, -28, 2, -12, 6, -8, 12, -4, 20, -4, 12, -2, 16, 0, 26, 36, 50, 48, 36, 50, 56, 44, 60, 60, 36, 52, 54, 28, 54, 52, 40, 60, 62, 48, 72, 72, 44, 72, 66, 48, 78, 82, 0, -4, 2, 0, -10, -6, 4, -10, 8, -24, -6, -14, 0
Offset: 1

Views

Author

Antti Karttunen, Mar 14 2018

Keywords

Crossrefs

Programs

  • Mathematica
    Table[DivisorSum[n, MoebiusMu[n/#] FromDigits[IntegerDigits[#, 3] /. 1 -> 0, 3] &], {n, 93}] (* Michael De Vlieger, Mar 17 2018 *)
  • PARI
    A300222(n) = fromdigits(apply(x->(if (1==x, 0, x)), digits(n, 3)), 3);
    A300822(n) = sumdiv(n,d,moebius(n/d)*A300222(d));

Formula

a(n) = Sum_{d|n} moebius(n/d)*A300222(d).
a(n) = A000010(n) - A300821(n).
a(n) = A300222(n) - A300824(n).

A300823 Difference between A244042 and its Möbius transform.

Original entry on oeis.org

0, 1, 1, 0, 1, 2, 1, 4, 3, 2, 1, 4, 1, 0, 5, 0, 1, 6, 1, 14, 3, 8, 1, 8, 3, 12, 9, 16, 1, 14, 1, 10, 11, 8, 3, 12, 1, 0, 15, -4, 1, 12, 1, 8, 15, 2, 1, 10, 1, 8, 11, 4, 1, 18, 11, 24, 3, 26, 1, 28, 1, 30, 9, 30, 15, 20, 1, 32, 5, 46, 1, 24, 1, 36, 7, 40, 9, 24, 1, 50, 27, 38, 1, 60, 11, 36, 29, 32, 1, 42, 13, 32, 33, 26, 3, 50, 1
Offset: 1

Views

Author

Antti Karttunen, Mar 14 2018

Keywords

Crossrefs

Programs

  • Mathematica
    f[n_] := FromDigits[IntegerDigits[n, 3] /. 2 -> 0, 3]; Table[f@ n - DivisorSum[n, MoebiusMu[n/#] f@ # &], {n, 97}] (* Michael De Vlieger, Mar 17 2018 *)
  • PARI
    A244042(n) = fromdigits(apply(x->(x%2), digits(n, 3)), 3);
    A300823(n) = -sumdiv(n,d,(dA244042(d));

Formula

a(n) = A244042(n) - A300821(n).
a(n) = -Sum_{d|n, dA008683(n/d)*A244042(d) = Sum_{d|n, dA300821(d).
a(n) = A051953(n) - A300824(n).

A359601 Dirichlet inverse of A244042, where A244042(n) replaces 2's with 0's in the ternary representation of n.

Original entry on oeis.org

1, 0, -3, -4, -3, 0, -1, 0, 0, -10, -9, 12, -13, -12, 9, 6, -9, 0, -1, 24, 3, -4, -3, 0, 8, 0, 0, -20, -27, 30, -31, -30, 27, -28, -21, 0, -37, -36, 39, 40, -39, 36, -37, 36, 0, -28, -27, -18, -30, 30, 27, 76, -27, 0, 53, 96, 3, -4, -3, -72, -1, 0, 0, 6, 69, 12, -13, 60, 9, 82, -9, 0, -1, 0, -24, 4, 15
Offset: 1

Views

Author

Antti Karttunen, Jan 11 2023

Keywords

Crossrefs

Cf. A056911 (positions of odd terms), A323239 (parity of terms), A337945.

Programs

  • PARI
    A244042(n) = fromdigits(apply(x->(x%2), digits(n, 3)), 3);
    memoA359601 = Map();
    A359601(n) = if(1==n,1,my(v); if(mapisdefined(memoA359601,n,&v), v, v = -sumdiv(n,d,if(dA244042(n/d)*A359601(d),0)); mapput(memoA359601,n,v); (v)));

Formula

a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, dA244042(n/d) * a(d).
a(n) = A359602(n) - A244042(n).
Showing 1-3 of 3 results.