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 1-10 of 11 results. Next

A014311 Numbers with exactly 3 ones in binary expansion.

Original entry on oeis.org

7, 11, 13, 14, 19, 21, 22, 25, 26, 28, 35, 37, 38, 41, 42, 44, 49, 50, 52, 56, 67, 69, 70, 73, 74, 76, 81, 82, 84, 88, 97, 98, 100, 104, 112, 131, 133, 134, 137, 138, 140, 145, 146, 148, 152, 161, 162, 164, 168, 176, 193, 194, 196, 200, 208, 224, 259, 261, 262, 265, 266, 268, 273, 274, 276, 280, 289, 290, 292, 296, 304
Offset: 1

Views

Author

Al Black (gblack(AT)nol.net)

Keywords

Comments

Equivalently, sums of three distinct powers of 2.
Appears to give all n such that 64 is the highest power of 2 dividing A005148(n). - Benoit Cloitre, Jun 22 2002
From Gus Wiseman, Oct 05 2020: (Start)
These are numbers k such that the k-th composition in standard order has length 3. The k-th composition in standard order (graded reverse-lexicographic, A066099) is obtained by taking the set of positions of 1's in the reversed binary expansion of k, prepending 0, taking first differences, and reversing again. This gives a bijective correspondence between nonnegative integers and integer compositions. The sequence together with the corresponding standard compositions begins:
7: (1,1,1) 44: (2,1,3) 97: (1,5,1)
11: (2,1,1) 49: (1,4,1) 98: (1,4,2)
13: (1,2,1) 50: (1,3,2) 100: (1,3,3)
14: (1,1,2) 52: (1,2,3) 104: (1,2,4)
19: (3,1,1) 56: (1,1,4) 112: (1,1,5)
21: (2,2,1) 67: (5,1,1) 131: (6,1,1)
22: (2,1,2) 69: (4,2,1) 133: (5,2,1)
25: (1,3,1) 70: (4,1,2) 134: (5,1,2)
26: (1,2,2) 73: (3,3,1) 137: (4,3,1)
28: (1,1,3) 74: (3,2,2) 138: (4,2,2)
35: (4,1,1) 76: (3,1,3) 140: (4,1,3)
37: (3,2,1) 81: (2,4,1) 145: (3,4,1)
38: (3,1,2) 82: (2,3,2) 146: (3,3,2)
41: (2,3,1) 84: (2,2,3) 148: (3,2,3)
42: (2,2,2) 88: (2,1,4) 152: (3,1,4)
(End)

Crossrefs

Cf. A038465 (base 3), A038471 (base 4), A038475 (base 5).
Cf. A081091 (primes), A212190 (squares), A212192 (triangular numbers), A173589 (Fibbinary).
Cf. A057168.
Cf. A000079, A018900, A014311, A014312, A014313, A023688, A023689, A023690, A023691 (Hammingweight = 1, 2, ..., 9).
A000217(n-2) counts compositions into three parts.
A001399(n-3) = A069905(n) = A211540(n+2) counts the unordered case.
A001399(n-6) = A069905(n-3) = A211540(n-1) counts the unordered strict case.
A001399(n-6)*6 = A069905(n-3)*6 = A211540(n-1)*6 counts the strict case.
A014612 is an unordered version, with strict case A007304.
A337453 is the strict case.
A337461 counts the coprime case.
A033992 lists numbers divisible by exactly three different primes.
A323024 lists numbers with exactly three different prime multiplicities.

Programs

  • C
    unsigned hakmem175(unsigned x) {
        unsigned s, o, r;
        s = x & -x;  r = x + s;
        o = r ^ x;  o = (o >> 2) / s;
        return r | o;
    }
    unsigned A014311(int n) {
        if (n == 1) return 7;
        return hakmem175(A014311(n - 1));
    }  // Peter Luschny, Jan 01 2014
    
  • Haskell
    a014311 n = a014311_list !! (n-1)
    a014311_list = [2^x + 2^y + 2^z |
                    x <- [2..], y <- [1..x-1], z <- [0..y-1]]
    -- Reinhard Zumkeller, May 03 2012
    
  • Mathematica
    Select[Range[200], (Count[IntegerDigits[#, 2], 1] == 3)&]
    nn = 8; Flatten[Table[2^i + 2^j + 2^k, {i, 2, nn}, {j, 1, i - 1}, {k, 0, j - 1}]] (* T. D. Noe, Nov 05 2013 *)
  • PARI
    for(n=0,10^3,if(hammingweight(n)==3,print1(n,", "))); \\ Joerg Arndt, Mar 04 2014
    
  • PARI
    print1(t=7);for(i=2,50,print1(","t=A057168(t))) \\ M. F. Hasler, Aug 27 2014
    
  • Python
    A014311_list = [2**a+2**b+2**c for a in range(2,6) for b in range(1,a) for c in range(b)] # Chai Wah Wu, Jan 24 2021
    
  • Python
    from itertools import islice
    def A014311_gen(): # generator of terms
        yield (n:=7)
        while True: yield (n:=n^((a:=-n&n+1)|(a>>1)) if n&1 else ((n&~(b:=n+(a:=n&-n)))>>a.bit_length())^b)
    A014311_list = list(islice(A014311_gen(),20)) # Chai Wah Wu, Mar 10 2025
    
  • Python
    from math import isqrt, comb
    from sympy import integer_nthroot
    def A014311(n): return (1<<(r:=n-1-comb((m:=integer_nthroot(6*n,3)[0])+(t:=(n>comb(m+2,3)))+1,3))-comb((k:=isqrt(b:=r+1<<1))+(b>k*(k+1)),2))+(1<<(a:=isqrt(s:=n-comb(m-(t^1)+2,3)<<1))+((s<<2)>(a<<2)*(a+1)+1))+(1<Chai Wah Wu, Mar 10 2025

Formula

A000120(a(n)) = 3. - Reinhard Zumkeller, May 03 2012
Start with A084468. If n is in sequence, then 2n is too. - Ralf Stephan, Aug 16 2013
a(n+1) = A057168(a(n)). - M. F. Hasler, Aug 27 2014
a(n) = 2^A056558(n-1) + 2^A194848(n-1) + 2^A194847(n-1). - Ridouane Oudra, Sep 06 2020
Sum_{n>=1} 1/a(n) = A367110 = 1.428591545852638123996854844400537952781688750906133068397189529775365950039... (calculated using Baillie's irwinSums.m, see Links). - Amiram Eldar, Feb 14 2022

Extensions

Extension and program by Olivier Gérard

A056558 Third tetrahedral coordinate, i.e., tetrahedron with T(t,n,k)=k; succession of growing finite triangles with increasing values towards bottom right.

Original entry on oeis.org

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

Views

Author

Henry Bottomley, Jun 26 2000

Keywords

Comments

Alternatively, write n = C(i,3)+C(j,2)+C(k,1) with i>j>k>=0; sequence gives k values. See A194847 for further information about this interpretation.
If {(X,Y,Z)} are triples of nonnegative integers with X>=Y>=Z ordered by X, Y and Z, then X=A056556(n), Y=A056557(n) and Z=A056558(n).
This is a 'Matryoshka doll' sequence with alpha=0 (cf. A000292 and A000178). - Peter Luschny, Jul 14 2009

Examples

			First triangle: [0]; second triangle: [0; 0 1]; third triangle: [0; 0 1; 0 1 2]; ...
		

References

  • D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.3, Eq. (20), p. 360.

Crossrefs

Together with A056559 and A056560 might enable reading "by antidiagonals" of cube arrays as 3-dimensional analog of A002262 and A025581 with square arrays. Also cf. A000292, A056556, A056557.
See also A194847, A194848, A194849.

Programs

  • Haskell
    import Data.List (inits)
    a056558 n = a056558_list !! n
    a056558_list = concatMap (concat . init . inits . enumFromTo 0) [0..]
    -- Reinhard Zumkeller, Jun 01 2015
    
  • Maple
    seq(seq(seq(i,i=0..k),k=0..n),n=0..6); # Peter Luschny, Sep 22 2011
  • Mathematica
    Table[i, {k, 0, 7}, {j, 0, k}, {i, 0, j}] // Flatten  (* Robert G. Wilson v, Sep 27 2011 *)
  • PARI
    T(t,n,k)=k \\ Charles R Greathouse IV, Feb 22 2017
    
  • Python
    from math import isqrt, comb
    from sympy import integer_nthroot
    def A056558(n): return (r:=n-comb((m:=integer_nthroot(6*(n+1),3)[0])+(n>=comb(m+2,3))+1,3))-comb((k:=isqrt(m:=r+1<<1))+(m>k*(k+1)),2) # Chai Wah Wu, Nov 04 2024

Formula

a(n) = n-A056556(n)*(A056556(n)+1)*(A056556(n)+2)/6-A056557(n)*(A056557(n)+1)/2 = n-A000292(A056556(n)-1)-A000217(A056557(n)) = A056557(n)-A056560(n).
a(n+1) = A056556(n)==a(n) ? 0 : A056557(n)==a(n) ? 0 : a(n)+1. - Graeme McRae, Jan 09 2007

A056556 First tetrahedral coordinate; repeat m (m+1)*(m+2)/2 times.

Original entry on oeis.org

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

Views

Author

Henry Bottomley, Jun 26 2000

Keywords

Comments

If {(X,Y,Z)} are triples of nonnegative integers with X >= Y >= Z ordered by X, Y and Z, then X=A056556(n), Y=A056557(n) and Z=A056558(n).
From Gus Wiseman, Jul 03 2019: (Start)
Also the maximum number of distinct multiplicities among integer partitions of n. For example, random partitions of 56 realizing each number of distinct multiplicities are:
1: (24,17,6,5,3,1)
2: (10,9,9,5,5,4,4,3,3,2,1,1)
3: (6,5,5,5,4,4,4,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)
4: (28,5,5,3,3,3,2,2,1,1,1,1,1)
5: (13,4,4,4,4,4,3,3,3,2,2,2,2,2,2,1,1)
6: (6,5,5,4,4,4,3,3,3,3,2,2,2,2,2,1,1,1,1,1,1)
The maximum number of distinct multiplicities is 6, so a(56) = 6.
(End)

Examples

			3 is (3+1) * (3+2)/2 = 10 times in the sequence all these occurrences are in consecutive places. The first 3 is at position binomial(3 + 2, 3) = 10, the last one at binomial((3 + 1) + 2, 3) - 1. - _David A. Corneth_, Oct 14 2022
		

Crossrefs

Programs

  • Mathematica
    Table[Table[m, {(m+1)(m+2)/2}], {m, 0, 7}] // Flatten (* Jean-François Alcover, Feb 28 2019 *)
  • PARI
    a(n)=my(t=polrootsreal(x^3+3*x^2+2*x-6*n)); t[#t]\1 \\ Charles R Greathouse IV, Feb 22 2017
    
  • Python
    from math import comb
    from sympy import integer_nthroot
    def A056556(n): return (m:=integer_nthroot(6*(n+1),3)[0])-(nChai Wah Wu, Nov 04 2024

Formula

a(n) = floor(x) where x is the (largest real) solution to x^3 + 3x^2 + 2x - 6n = 0; a(A000292(n)) = n+1.
a(n+1) = a(n)+1 if a(n) = A056558(n), otherwise a(n). - Graeme McRae, Jan 09 2007
a(n) = floor(t/3 + 1/t - 1), where t = (81*n + 3*sqrt(729*n^2 - 3))^(1/3). - Ridouane Oudra, Mar 21 2021
a(n) = floor(t + 1/(3*t) - 1), where t = (6*n)^(1/3), for n>=1. - Ridouane Oudra, Nov 04 2022
a(n) = m if n>=binomial(m+2,3) and a(n) = m-1 otherwise where m = floor((6n+6)^(1/3)). - Chai Wah Wu, Nov 04 2024

Extensions

Incorrect formula deleted by Ridouane Oudra, Nov 04 2022

A056557 Second tetrahedral coordinate.

Original entry on oeis.org

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

Views

Author

Henry Bottomley, Jun 26 2000

Keywords

Comments

If {(X,Y,Z)} are triples of nonnegative integers with X >= Y >= Z ordered by X, Y and Z, then X=A056556(n), Y=A056557(n) and Z=A056558(n).

Crossrefs

Programs

  • Python
    from math import isqrt, comb
    from sympy import integer_nthroot
    def A056557(n): return (k:=isqrt(r:=n+1-comb((m:=integer_nthroot(6*(n+1),3)[0])-(nChai Wah Wu, Nov 04 2024

Formula

a(n) = floor((sqrt(8*(n-A056556(n)*(A056556(n)+1)*(A056556(n)+2)/6)+1)-1)/2) = A003056(n-A000292(A056556(n)-1)).
a(n+1) = 0 if A056556(n) = A056558(n); a(n+1) = a(n)+1 if a(n) = A056558(n); otherwise a(n+1) = a(n). - Graeme McRae, Jan 09 2007

A194848 Write n = C(i,3)+C(j,2)+C(k,1) with i>j>k>=0; sequence gives j values.

Original entry on oeis.org

1, 1, 2, 2, 1, 2, 2, 3, 3, 3, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 1, 2, 2
Offset: 0

Views

Author

N. J. A. Sloane, Sep 03 2011

Keywords

Comments

See A194847.

References

  • D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.3, Eq. (20), p. 360.

Crossrefs

The [i,j,k] values are [A194847, A194848, A056558].

Programs

  • Maple
    See A194847.
  • Python
    from math import isqrt, comb
    from sympy import integer_nthroot
    def A194848(n): return (k:=isqrt(r:=n+1-comb((m:=integer_nthroot(6*(n+1),3)[0])-(n(k<<2)*(k+1)+1) # Chai Wah Wu, Nov 04 2024

Formula

Equals A056557(n) + 1.

A194882 Write n = C(i,4)+C(j,3)+C(k,2)+C(l,1) with i>j>k>l>=0; sequence gives i values.

Original entry on oeis.org

3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
Offset: 0

Views

Author

N. J. A. Sloane, Sep 04 2011

Keywords

Comments

Each n >= 0 has a unique representation as n = C(i,4)+C(j,3)+C(k,2)+C(l.1) with i>j>k>l>=0. This is the combinatorial number system of degree t = 4, where we get [A194882, A194883, A194884, A127324]. For degree t = 3 see A194847.

References

  • D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.3, Eq. (20), p. 360.

Crossrefs

Programs

  • Python
    from math import comb
    from sympy import integer_nthroot
    def A194882(n): return (m:=integer_nthroot(24*(n+2),4)[0]+1)+(n>=comb(m+1,4)) # Chai Wah Wu, Dec 10 2024

Formula

a(n) = m if n < binomial(m+1,4) and a(n) = m+1 otherwise where m = 1+floor((24*(n+2))^(1/4)). - Chai Wah Wu, Dec 10 2024

A194883 Write n = C(i,4)+C(j,3)+C(k,2)+C(l,1) with i>j>k>l>=0; sequence gives j values.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Sep 04 2011

Keywords

Comments

Each n >= 0 has a unique representation as n = C(i,4)+C(j,3)+C(k,2)+C(l.1) with i>j>k>l>=0. This is the combinatorial number system of degree t = 4, where we get [A194882, A194883, A194884, A127324]. For degree t = 3 see A194847.

References

  • D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.3, Eq. (20), p. 360.

Crossrefs

A194884 Write n = C(i,4)+C(j,3)+C(k,2)+C(l,1) with i>j>k>l>=0; sequence gives k values.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Sep 04 2011

Keywords

Comments

Each n >= 0 has a unique representation as n = C(i,4)+C(j,3)+C(k,2)+C(l.1) with i>j>k>l>=0. This is the combinatorial number system of degree t = 4, where we get [A194882, A194883, A194884, A127324]. For degree t = 3 see A194847.

References

  • D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.3, Eq. (20), p. 360.

Crossrefs

A194849 Write n = C(i,3)+C(j,2)+C(k,1) with i>j>k>=0; let L[n] = [i,j,k]; sequence gives list of triples L[n], n >= 0.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Sep 03 2011

Keywords

Examples

			List of triples begins:
[2, 1, 0]
[3, 1, 0]
[3, 2, 0]
[3, 2, 1]
[4, 1, 0]
[4, 2, 0]
[4, 2, 1]
[4, 3, 0]
[4, 3, 1]
[4, 3, 2]
...
		

References

  • D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.3, Eq. (20), p. 360.

Crossrefs

The three columns are [A194847, A194848, A056558], or equivalently [A056556+2, A056557+1, A056558]. See A194847 for further information.

A194885 Write n = C(i,4)+C(j,3)+C(k,2)+C(l,1) with i>j>k>l>=0; let L[n] = [i,j,k,l]; sequence gives list of quadruples L[n], n >= 0.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Sep 04 2011

Keywords

Comments

Each n >= 0 has a unique representation as n = C(i,4)+C(j,3)+C(k,2)+C(l.1) with i>j>k>l>=0. This is the combinatorial number system of degree t = 4, where we get [A194882, A194883, A194884, A127324]. For degree t = 3 see A194847.

Examples

			List of quadruples begins:
[3, 2, 1, 0]
[4, 2, 1, 0]
[4, 3, 1, 0]
[4, 3, 2, 0]
[4, 3, 2, 1]
[5, 2, 1, 0]
[5, 3, 1, 0]
[5, 3, 2, 0]
[5, 3, 2, 1]
[5, 4, 1, 0]
[5, 4, 2, 0]
...
		

References

  • D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.3, Eq. (20), p. 360.

Crossrefs

The four columns are [A194882, A194883, A194885, A127324], or equivalently [A127321+3, A127322+2, A127323+1, A127324].
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