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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A168186 Positive numbers that are not multiples of 12.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78
Offset: 1

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Author

Reinhard Zumkeller, Nov 30 2009

Keywords

Comments

121 (in decimal) is a member of this sequence but not a member of A023805. - Robert Munafo, Jan 26 2010
80 is a member of this sequence but is not a member of A160453. - Franklin T. Adams-Watters, Jan 26 2010

Examples

			156 is in A023805 but not in this sequence. - _Franklin T. Adams-Watters_, Jan 26 2010
		

Crossrefs

Complement of A008594.
All three of A023805, A160453, A168186 are different.

Programs

Formula

A168185(a(n)) = 1.
A109015(a(n)) < 12.
From Chai Wah Wu, Jan 16 2020: (Start)
a(n) = a(n-1) + a(n-11) - a(n-12) for n > 12.
G.f.: x*(x^11 + x^10 + x^9 + x^8 + x^7 + x^6 + x^5 + x^4 + x^3 + x^2 + x + 1)/(x^12 - x^11 - x + 1). (End)
Sum_{n>=1} (-1)^(n+1)/a(n) = (12*sqrt(6) - 4*sqrt(3) + 6*sqrt(2) - 15)*Pi/72. - Amiram Eldar, May 12 2025

A023805 Xenodromes: all digits in base 11 are different.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74
Offset: 1

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Author

Keywords

Comments

Considering some base b, there are b numbers with 1 digit, (b-1)*(b-1) numbers with 2 digits -- since leading 0's are not allowed and the second digit must avoid the first. There are (b-1)*(b-1)*(b-2) numbers with 3 digits, (b-1)*(b-1)*(b-2)*..*(b-d+1) numbers with d digits, in total b+(b-1)*sum_{d=2..b} (b-1)!/(b-d)! = b+(b-1)^2* 2F0(1,2-b;;-1) = A001339(b-1). The formula is applicable to sequences A023798 - A023810. This sequence here as A001339(11-1) = 98641011 terms. [From R. J. Mathar, Jan 27 2010]
Last term is a(98641011) = 282458553905. - Charles R Greathouse IV, Jun 16 2012

Examples

			121 (in decimal) = 100 (base 11) is a member of A168186 but not a member of this sequence. - Robert Munafo, Jan 26 2010
156 is in A023805 but not in A168186. - Franklin T. Adams-Watters, Jan 26 2010
		

Crossrefs

All three of A023805, A160453, A168186 are different.

Programs

  • Mathematica
    Select[Range[0, 100], Max[DigitCount[#, 11]] == 1 &] (* Paolo Xausa, Mar 22 2025 *)
Showing 1-2 of 2 results.