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.

A364288 a(n) = n - A243071(n).

Original entry on oeis.org

1, 1, 0, 2, -2, 0, -8, 4, 4, -4, -20, 0, -50, -16, 2, 8, -110, 8, -236, -8, -8, -40, -488, 0, 14, -100, 18, -32, -994, 4, -2016, 16, -28, -220, 8, 16, -4058, -472, -86, -16, -8150, -16, -16340, -80, 20, -976, -32720, 0, 26, 28, -202, -200, -65482, 36, -4, -64, -452, -1988, -131012, 8, -262082, -4032, 6, 32, -58, -56
Offset: 1

Views

Author

Antti Karttunen, Jul 25 2023

Keywords

Crossrefs

Cf. A243071, A364256 [= gcd(n,a(n))], A364258.
Cf. A007283 (positions of 0's, conjectured), A364289 (positions of terms <= 0), A364290 (of terms > 0), A364291 (of terms >= 0).
Cf. also A364253.

Programs

  • Mathematica
    nn = 60; f[x_] := Times @@ Power[Which[# == 1, 1, # == 2, 1, True, NextPrime[#, -1]] & /@ First[#], Last[#] ] &@ Transpose@ FactorInteger@ x; Do[a[n] = Which[n <= 2, n - 1, OddQ[n], 1 + 2 a[f[n]], True, 2 a[n/2] ], {n, nn}]; Array[# - a[#] &, nn] (* Michael De Vlieger, Jul 25 2023 *)
  • PARI
    A064989(n) = { my(f=factor(n>>valuation(n,2))); for(i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f); };
    A243071(n) = if(n<=2, n-1, if(!(n%2), 2*A243071(n/2), 1+(2*A243071(A064989(n)))));
    A364288(n) = (n-A243071(n));

Formula

a(n) = A364258(A243071(n)).
For n >= 1, a(2*n) = 2*a(n).
For n >= 0, a(A007283(n)) = 0.

A364254 a(n) = gcd(n, A332215(n)).

Original entry on oeis.org

1, 1, 3, 2, 5, 6, 7, 4, 1, 10, 1, 12, 1, 14, 1, 8, 1, 2, 1, 20, 1, 2, 23, 24, 1, 2, 9, 28, 1, 2, 31, 16, 1, 2, 1, 4, 1, 2, 1, 40, 1, 2, 1, 4, 3, 46, 1, 48, 1, 2, 1, 4, 1, 18, 1, 56, 1, 2, 1, 4, 1, 62, 1, 32, 1, 2, 1, 4, 1, 2, 1, 8, 1, 2, 15, 4, 1, 2, 1, 80, 1, 2, 1, 4, 5, 2, 1, 8, 1, 6, 13, 92, 1, 2, 1, 96, 1, 2, 3, 4
Offset: 1

Views

Author

Antti Karttunen, Jul 16 2023

Keywords

Crossrefs

Cf. also A364255.

Formula

a(n) = gcd(n, A364253(n)) = gcd(A332215(n), A364253(n)).

A366372 a(n) = A332214(n) - n, where A332214 is the Mersenne-prime fixing variant of permutation A163511.

Original entry on oeis.org

1, 1, 2, 0, 4, 4, 0, 0, 8, 18, 8, 38, 0, 8, 0, -10, 16, 64, 36, 324, 16, 126, 76, 2, 0, 38, 16, 8, 0, -14, -20, 0, 32, 210, 128, 2366, 72, 992, 648, 86, 32, 400, 252, 132, 152, 30, 4, 914, 0, 140, 76, 194, 32, 52, 16, 100, 0, -12, -28, 158, -40, 32, 0, -52, 64, 664, 420, 16740, 256, 7134, 4732, 554, 144, 3014, 1984
Offset: 0

Views

Author

Antti Karttunen, Oct 08 2023

Keywords

Crossrefs

Cf. A332214, A335431 (known positions of 0's), A366373, A366374, A366375, A366376.
Cf. also A364253, A364258, A366282.

Programs

Showing 1-3 of 3 results.