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.

A249779 Row "sums" of Pascal triangle (A007318), using operation <+> defined in comment in A245618.

Original entry on oeis.org

1, 2, 2, 2, 2, 22, 20, 28, 2, 494, 912, 1672, 2376, 4836, 4160, 4184, 2, 131038, 261800, 522272, 1035804, 2053288, 3977272, 7742352, 13942968, 28016020, 47111040, 84948528, 92072064, 272727022, 249686810, 167376688, 2, 8589934526, 17179867992, 34359725136
Offset: 0

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Author

Vladimir Shevelev, Nov 05 2014

Keywords

Comments

Operation <+> is defined in A245618 as: k<+>m = |k+(-1)^(k+m)*m|.
a(n)=2 for n=1,2,3,4,8,16,32,64,128,256,...

Examples

			For n=4, we have row 1,4,6,4,1.
By definition of <+>, we find 1<+>4=3, 3<+>6=3, 3<+>4=1, 1<+>1=2. So a(4)=2.
		

Crossrefs

Programs

  • Mathematica
    a249779[n_Integer] := Module[{m0082, pls, lst},
      m0082[j_] := Table[Binomial[j, k], {k, 0, j}];
      pls[k_, m_] := Abs[k + (-1)^(k + m)*m];
      lst = m0082[n];
      For[i = 0, i < n, i++, lst[[2]] = pls[lst[[1]], lst[[2]]];
       lst = Drop[lst, 1]];
      lst[[1]]
    ]; a249779 /@ Range[35] (* Michael De Vlieger, Nov 23 2014 *)
    parityAdd[a_,b_]:=Abs[a+b (-1)^(a+b)];
    Map[Fold[parityAdd,First[#],Rest[#]]&[Binomial[#,Range[0,#]]]&,Range[0,35]] (* Peter J. C. Moses, Dec 01 2014 *)

Extensions

More terms from Peter J. C. Moses, Nov 05 2014