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 1-6 of 6 results.

A265705 Triangle read by rows: T(n,k) = k IMPL n, 0 <= k <= n, bitwise logical IMPL.

Original entry on oeis.org

0, 1, 1, 3, 2, 3, 3, 3, 3, 3, 7, 6, 5, 4, 7, 7, 7, 5, 5, 7, 7, 7, 6, 7, 6, 7, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 15, 14, 13, 12, 11, 10, 9, 8, 15, 15, 15, 13, 13, 11, 11, 9, 9, 15, 15, 15, 14, 15, 14, 11, 10, 11, 10, 15, 14, 15, 15, 15, 15, 15, 11, 11, 11, 11, 15
Offset: 0

Views

Author

Reinhard Zumkeller, Dec 15 2015

Keywords

Examples

			.          10 | 1010                            12 | 1100
.           4 |  100                             6 |  110
.   ----------+-----                     ----------+-----
.   4 IMPL 10 | 1011 -> T(10,4)=11       6 IMPL 12 | 1101 -> T(12,6)=13
.
First 16 rows of the triangle, where non-symmetrical rows are marked, see comment concerning A158582 and A089633:
.   0:                                 0
.   1:                               1   1
.   2:                             3   2   3
.   3:                           3   3   3   3
.   4:                         7   6   5   4   7    X
.   5:                       7   7   5   5   7   7
.   6:                     7   6   7   6   7   6   7
.   7:                   7   7   7   7   7   7   7   7
.   8:                15  14  13  12  11  10   9   8  15    X
.   9:              15  15  13  13  11  11   9   9  15  15    X
.  10:            15  14  15  14  11  10  11  10  15  14  15    X
.  11:          15  15  15  15  11  11  11  11  15  15  15  15
.  12:        15  14  13  12  15  14  13  12  15  14  13  12  15    X
.  13:      15  15  13  13  15  15  13  13  15  15  13  13  15  15
.  14:    15  14  15  14  15  14  15  14  15  14  15  14  15  14  15
.  15:  15  15  15  15  15  15  15  15  15  15  15  15  15  15  15  15 .
		

Crossrefs

Cf. A003817, A007088, A029578, A089633, A158582, A247648, A265716 (central terms), A265736 (row sums).
Other triangles: A080099 (AND), A080098 (OR), A051933 (XOR), A102037 (CNIMPL).

Programs

  • Haskell
    a265705_tabl = map a265705_row [0..]
    a265705_row n = map (a265705 n) [0..n]
    a265705 n k = k `bimpl` n where
       bimpl 0 0 = 0
       bimpl p q = 2 * bimpl p' q' + if u <= v then 1 else 0
                   where (p', u) = divMod p 2; (q', v) = divMod q 2
    
  • Julia
    using IntegerSequences
    for n in 0:15 println(n == 0 ? [0] : [Bits("IMP", k, n) for k in 0:n]) end  # Peter Luschny, Sep 25 2021
  • Maple
    A265705 := (n, k) -> Bits:-Implies(k, n):
    seq(seq(A265705(n, k), k=0..n), n=0..11); # Peter Luschny, Sep 23 2019
  • Mathematica
    T[n_, k_] := If[n == 0, 0, BitOr[2^Length[IntegerDigits[n, 2]]-1-k, n]];
    Table[T[n, k], {n, 0, 11}, {k, 0, n}] // Flatten (* Jean-François Alcover, Sep 25 2021, after David A. Corneth's PARI code *)
  • PARI
    T(n, k) = if(n==0,return(0)); bitor((2<David A. Corneth, Sep 24 2021
    

Formula

T(n,0) = T(n,n) = A003817(n).
T(2*n,n) = A265716(n).
Let m = A089633(n): T(m,k) = T(m,m-k), k = 0..m.
Let m = A158582(n): T(m,k) != T(m,m-k) for at least one k <= n.
Let m = A247648(n): T(2*m,m) = 2*m.
For n > 0: A029578(n+2) = number of odd terms in row n; no even terms in odd-indexed rows.
A265885(n) = T(prime(n),n).
A053644(n) = smallest k such that row k contains n.

A080098 Triangle T(n,k) = n OR k, 0 <= k <= n, bitwise logical OR, read by rows.

Original entry on oeis.org

0, 1, 1, 2, 3, 2, 3, 3, 3, 3, 4, 5, 6, 7, 4, 5, 5, 7, 7, 5, 5, 6, 7, 6, 7, 6, 7, 6, 7, 7, 7, 7, 7, 7, 7, 7, 8, 9, 10, 11, 12, 13, 14, 15, 8, 9, 9, 11, 11, 13, 13, 15, 15, 9, 9, 10, 11, 10, 11, 14, 15, 14, 15, 10, 11, 10, 11, 11, 11, 11, 15, 15, 15, 15, 11, 11, 11, 11, 12, 13, 14, 15, 12, 13, 14, 15, 12, 13, 14, 15, 12
Offset: 0

Views

Author

Reinhard Zumkeller, Jan 28 2003

Keywords

Examples

			Triangle begins:
   0,
   1,  1,
   2,  3,  2,
   3,  3,  3,  3,
   4,  5,  6,  7,  4,
   5,  5,  7,  7,  5,  5,
   6,  7,  6,  7,  6,  7,  6,
   7,  7,  7,  7,  7,  7,  7,  7,
   8,  9, 10, 11, 12, 13, 14, 15,  8,
   9,  9, 11, 11, 13, 13, 15, 15,  9,  9,
  10, 11, 10, 11, 14, 15, 14, 15, 10, 11, 10,
  ...
		

Crossrefs

Cf. A001316 (number of integers k such that T(n, k) = n in n-th row).
Cf. A350093 (row sums), A003986 (array).
Other triangles: A080099 (AND), A051933 (XOR), A265705 (IMPL), A102037 (CNIMPL).

Programs

  • Haskell
    import Data.Bits ((.|.))
    a080098 n k = n .|. k :: Int
    a080098_row n = map (a080098 n) [0..n]
    a080098_tabl = map a080098_row [0..]
    -- Reinhard Zumkeller, Aug 03 2014, Jul 05 2012
    
  • Mathematica
    T[n_, k_] := n ~BitOr~ k;
    Table[T[n, k], {n, 0, 12}, {k, 0, n}] // Flatten (* Jean-François Alcover, Dec 01 2021 *)
  • Python
    def T(n, k): return n | k
    print([T(n, k) for n in range(13) for k in range(n+1)]) # Michael S. Branicky, Dec 01 2021

A080099 Triangle T(n,k) = n AND k, 0<=k<=n, bitwise logical AND, read by rows.

Original entry on oeis.org

0, 0, 1, 0, 0, 2, 0, 1, 2, 3, 0, 0, 0, 0, 4, 0, 1, 0, 1, 4, 5, 0, 0, 2, 2, 4, 4, 6, 0, 1, 2, 3, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0, 8, 0, 1, 0, 1, 0, 1, 0, 1, 8, 9, 0, 0, 2, 2, 0, 0, 2, 2, 8, 8, 10, 0, 1, 2, 3, 0, 1, 2, 3, 8, 9, 10, 11, 0, 0, 0, 0, 4, 4, 4, 4, 8, 8, 8, 8, 12, 0, 1, 0, 1, 4, 5, 4, 5, 8, 9, 8, 9
Offset: 0

Views

Author

Reinhard Zumkeller, Jan 28 2003

Keywords

Comments

A080100(n) = number of numbers k such that n AND k = 0 in n-th row of the triangular array.

Examples

			Triangle starts:
0
0 1
0 0 2
0 1 2 3
0 0 0 0 4
0 1 0 1 4 5
0 0 2 2 4 4 6
0 1 2 3 4 5 6 7
...
		

Crossrefs

Cf. A080100, A222423 (row sums), A004198 (array).
Other triangles: A080098 (OR), A051933 (XOR), A265705 (IMPL), A102037 (CNIMPL).

Programs

  • Haskell
    import Data.Bits ((.&.))
    a080099 n k = n .&. k :: Int
    a080099_row n = map (a080099 n) [0..n]
    a080099_tabl = map a080099_row [0..]
    -- Reinhard Zumkeller, Aug 03 2014, Jul 05 2012
    
  • Mathematica
    Column[Table[BitAnd[n, k], {n, 0, 15}, {k, 0, n}], Center] (* Alonso del Arte, Jun 19 2012 *)
  • PARI
    T(n,k)=bitand(n,k) \\ Charles R Greathouse IV, Jan 26 2013
    
  • Python
    def T(n, k): return n & k
    print([T(n, k) for n in range(14) for k in range(n+1)]) # Michael S. Branicky, Dec 16 2021

A224915 a(n) = Sum_{k=0..n} n XOR k where XOR is the bitwise logical exclusive-or operator.

Original entry on oeis.org

0, 1, 5, 6, 22, 23, 27, 28, 92, 93, 97, 98, 114, 115, 119, 120, 376, 377, 381, 382, 398, 399, 403, 404, 468, 469, 473, 474, 490, 491, 495, 496, 1520, 1521, 1525, 1526, 1542, 1543, 1547, 1548, 1612, 1613, 1617, 1618, 1634, 1635, 1639, 1640, 1896, 1897, 1901, 1902, 1918
Offset: 0

Views

Author

Alex Ratushnyak, Apr 19 2013

Keywords

Examples

			a(2) = (0 xor 2) + (1 xor 2) = 2 + 3 = 5.
		

Crossrefs

Cf. A001196 (bit doubling).
Row sums of A051933.
Other sums: A222423 (AND), A350093 (OR), A265736 (IMPL), A350094 (CNIMPL), A004125 (mod).

Programs

  • Maple
    read("transforms"):
    A051933 := proc(n,k)
        XORnos(n,k) ;
    end proc:
    A224915 := proc(n)
        add(A051933(n,k),k=0..n) ;
    end proc: # R. J. Mathar, Apr 26 2013
    # second Maple program:
    with(MmaTranslator[Mma]):
    seq(add(BitXor(n,i),i=0..n),n=0..60); # Ridouane Oudra, Dec 09 2020
  • Mathematica
    Array[Sum[BitXor[#, k], {k, 0, #}] &, 53, 0] (* Michael De Vlieger, Dec 09 2020 *)
  • PARI
    a(n) = sum(k=0, n, bitxor(n, k)); \\ Michel Marcus, Jun 08 2019
    
  • PARI
    a(n) = (3*fromdigits(binary(n),4) - n) >>1; \\ Kevin Ryde, Dec 17 2021
  • Python
    for n in range(59):
        s = 0
        for k in range(n):  s += n ^ k
        print(s, end=',')
    
  • Python
    def A224915(n): return 3*int(bin(n)[2:],4)-n>>1 # Chai Wah Wu, Aug 21 2023
    

Formula

a(n) = Sum_{j=1..n} 4^(v_2(j)), where v_2(j) is the exponent of highest power of 2 dividing j. - Ridouane Oudra, Jun 08 2019
a(n) = n + 3*Sum_{j=1..floor(log_2(n))} 4^(j-1)*floor(n/2^j), for n>=1. - Ridouane Oudra, Dec 09 2020
From Kevin Ryde, Dec 17 2021: (Start)
a(2*n+b) = 4*a(n) + n + b where b = 0 or 1.
a(n) = (A001196(n) - n)/2.
a(n) = A350093(n) - A222423(n), being XOR = OR - AND.
(End)

A102037 Triangle of BitAnd(BitNot(n), k).

Original entry on oeis.org

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

Views

Author

Eric W. Weisstein, Dec 25 2004

Keywords

Comments

As a logical operation on two variables this is also called the 'converse nonimplication'. - Peter Luschny, Sep 25 2021

Examples

			Table starts:
[0] 0;
[1] 0, 0;
[2] 0, 1, 0;
[3] 0, 0, 0, 0;
[4] 0, 1, 2, 3, 0;
[5] 0, 0, 2, 2, 0, 0;
[6] 0, 1, 0, 1, 0, 1, 0;
[7] 0, 0, 0, 0, 0, 0, 0, 0;
[8] 0, 1, 2, 3, 4, 5, 6, 7, 0;
[9] 0, 0, 2, 2, 4, 4, 6, 6, 0, 0.
		

Crossrefs

Cf. A350094 (row sums), A268040 (array).
Other triangles: A080099 (AND), A080098 (OR), A051933 (XOR), A265705 (IMPL).

Programs

  • Julia
    using IntegerSequences
    A102037Row(n) = [Bits("CNIMP", n, k) for k in 0:n]
    for n in 0:20 println(A102037Row(n)) end  # Peter Luschny, Sep 25 2021
  • Maple
    with(Bits): cnimp := (n, k) -> And(Not(n), k):
    seq(print(seq(cnimp(n,k), k=0..n)), n = 0..12); # Peter Luschny, Sep 25 2021

A375551 a(n) = Sum_{k=0..n} k XOR n-k, where XOR is the bitwise exclusive disjunction. Row sums of A003987.

Original entry on oeis.org

0, 2, 4, 12, 12, 22, 32, 56, 48, 58, 68, 100, 108, 142, 176, 240, 208, 210, 212, 252, 252, 294, 336, 424, 416, 458, 500, 596, 636, 734, 832, 992, 896, 866, 836, 876, 844, 886, 928, 1048, 1008, 1050, 1092, 1220, 1260, 1390, 1520, 1744, 1680, 1714, 1748, 1884, 1916
Offset: 0

Views

Author

Peter Luschny, Sep 27 2024

Keywords

Crossrefs

Programs

  • Maple
    XOR := (n, k) -> Bits:-Xor(n, k):
    a := n -> local k; add(XOR(k, n-k), k=0..n):
    seq(a(n), n = 0..52);
  • Mathematica
    (* Using definition *)
    Table[Sum[BitXor[n - k, k], {k, 0, n}], {n, 0, 100}]
    (* Using recurrence -- faster *)
    a[0] = 0; a[n_] := a[n] = If[OddQ[n], 4*a[(n-1)/2] + n + 1, 2*(a[n/2] + a[n/2-1])];
    Table[a[n], {n, 0, 100}] (* Paolo Xausa, Oct 01 2024 *)
  • PARI
    a(n) = sum(k=0, n, bitxor(k, n-k)); \\ Michel Marcus, Sep 28 2024

Formula

a(n) = 2*A099027(n).
a(n) = 2*n + A006582(n).
a(2^n - 1) = 4^n - 2^n = A020522(n).
a(2^n) = 4^n - 2^n*(n - 1) = 2*A376585(n).
Recurrence: a(0) = 0; a(2*n) = 2*(a(n) + a(n-1)); a(2*n+1) = 2*(2*a(n) + n + 1). - Paolo Xausa, Oct 01 2024, derived from recurrence in A099027.
Showing 1-6 of 6 results.