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 1-2 of 2 results.

A065003 Not McNugget numbers.

Original entry on oeis.org

1, 2, 3, 4, 5, 7, 8, 10, 11, 13, 14, 16, 17, 19, 22, 23, 25, 28, 31, 34, 37, 43
Offset: 1

Views

Author

Karl Sabbagh (karl.sabbagh(AT)btinternet.com), Nov 01 2001

Keywords

Comments

A McNugget number has the form 6x + 9y + 20z for nonnegative integers x, y, z.
A214772(a(n)) = 0. - Reinhard Zumkeller, Jul 28 2012

References

  • Eric Weisstein, Concise Encyclopedia of Mathematics, p. 1151.

Crossrefs

Cf. A214777 (complement).

Programs

  • Haskell
    import Data.List (elemIndices)
    a065003 n = a065003_list !! n
    a065003_list = elemIndices 0 $ map a214772 [0..43]
    -- Reinhard Zumkeller, Jul 28 2012
    
  • Mathematica
    Select[Range[43], Length@FrobeniusSolve[{6, 9, 20}, #] == 0 &] (* Arkadiusz Wesolowski, Feb 20 2013 *)
  • PARI
    is(n)=forstep(k=n,6,-20,if(k%3==0, return(0)));n%20>0 \\ Charles R Greathouse IV, May 05 2013

A214772 Number of partitions of n into parts 6, 9 or 20.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 1, 1, 0, 0, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 3, 0, 2, 2, 1, 1, 3, 0, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 4, 1, 3, 3, 2, 2, 5, 1, 3, 4, 2, 3, 5, 2, 3, 5, 2, 3, 6, 2, 4, 5, 3, 3, 7, 2, 5, 6, 3, 4, 7, 3
Offset: 0

Views

Author

Reinhard Zumkeller, Jul 28 2012

Keywords

Comments

a(A065003(n)) = 0; a(A214777(n)) > 0.

Examples

			a(10) = 0, cf. A065003(8) = 10;
a(20) = #{20} = 1;
a(30) = #{6+6+6+6+6, 6+6+9+9} = 2;
a(40) = #{20+20} = 1;
a(50) = #{5*6+20, 6+6+9+9+20} = 2;
a(60) = #{10*6, 7*6+9+9, 4*6+4*9, 6+6*9, 20+20+20} = 5;
a(70) = #{5*6+20+20, 6+6+9+9+20+20} = 2
a(80) = #{10*6+20, 7*6+9+9+20, 4*6+4*9+20, 6+6*99+20, 4*20} = 5;
a(90) = #{15*6, 12*6+9+9, 9*6+4*9, 6*6+6*99, 5*6+3*20, 3*6+8*9, 6+6+9+9+3*20, 10*9} = 8;
a(100) = #{10*6+2*20, 7*6+9+9+2*20, 4*6+4*9+2*20, 6+6*9+2*20, 5*20} = 5.
		

Programs

  • Haskell
    a214772 = p [6, 9, 20] where
       p _      0 = 1
       p []     _ = 0
       p ks'@(k:ks) m = if m < k then 0 else p ks' (m - k) + p ks m

Formula

G.f. 1/((1-x^6)*(1-x^9)*(1-x^20)). - R. J. Mathar, Jul 30 2012
Showing 1-2 of 2 results.