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.

A112060 Square array A(x,y) = y-th natural number k for which A112049(k)=x and 0 if no such k exists; read by antidiagonals A(1,1), A(2,1), A(1,2), A(3,1), A(2,2), ...

Original entry on oeis.org

1, 2, 3, 5, 4, 11, 6, 7, 12, 24, 9, 8, 23, 35, 60, 10, 15, 36, 59, 155, 84, 13, 16, 47, 95, 275, 239, 144, 14, 19, 48, 119, 335, 575, 779, 180, 17, 20, 71, 120, 359, 659, 1499, 2855, 264, 18, 27, 72, 179, 419, 839, 1535, 4199, 5279, 420, 21, 28, 83, 204, 504
Offset: 1

Views

Author

Antti Karttunen, Aug 27 2005

Keywords

Comments

This is a permutation of natural numbers provided that the sequence A112046 contains only prime values [which is true] and every prime occurs infinitely many times there.

Examples

			The top left corner of the array:
   1,  2,  5,  6,  9, 10, ...
   3,  4,  7,  8, 15, 16, ...
  11, 12, 23, 36, 47, ...
		

Crossrefs

A112070(x, y) = 2*A(X, Y)+1. Transpose: A112061. Column 1: A112051. Row 1: A042963, Row 2: A112062, Row 3: A112063, Row 4: A112064, Row 5: A112065, Row 6: A112066, Row 7: A112067, Row 8: A112068, Row 9: A112069.
Cf. also A227196.

A112132 Period 4: repeat [1, 3, 1, 7].

Original entry on oeis.org

1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1, 7, 1, 3, 1
Offset: 1

Views

Author

Antti Karttunen, Aug 28 2005

Keywords

Crossrefs

First differences of A112062.
Also half of the first differences of A112072. Cf. A112086.

Programs

Formula

a(n+1) = 3-2*sin(Pi*n/2)-2*(-1)^n. - R. J. Mathar, Oct 08 2011
Multiplicative with a(2) = 3, a(2^e) = 7 if e >= 2, a(p^e) = 1 otherwise. - Antti Karttunen, Mar 31 2013, typo corrected May 02 2020
From Wesley Ivan Hurt, Jul 09 2016: (Start)
G.f.: x*(1+3*x+x^2+7*x^3)/(1-x^4).
a(n) = a(n-4) for n>4.
a(2n) = 5+2*(-1)^n, a(2n-1) = 1. (End)
Dirichlet g.f.: zeta(s)*(1+2^(1-s)+4^(1-s)). - Amiram Eldar, Jan 03 2023

A112072 Odd numbers n for which 3 is the smallest i (>= 1) with Jacobi symbol J(i,n) getting either a value 0 or -1.

Original entry on oeis.org

7, 9, 15, 17, 31, 33, 39, 41, 55, 57, 63, 65, 79, 81, 87, 89, 103, 105, 111, 113, 127, 129, 135, 137, 151, 153, 159, 161, 175, 177, 183, 185, 199, 201, 207, 209, 223, 225, 231, 233, 247, 249, 255, 257, 271, 273, 279, 281, 295, 297, 303, 305, 319, 321, 327
Offset: 1

Views

Author

Antti Karttunen, Aug 27 2005

Keywords

Crossrefs

Row 2 of A112070. a(n) = 2*A112062(n)+1.
Showing 1-3 of 3 results.