login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A140820 Triangle read by rows: let c(i,k)=Floor[Mod[i/2^k, 2]]; b(i,k)=If[c[i, k] == 0 && c[i, k + 1] == 0, 0, If[c[ i, k] == 1 && c[i, k + 1] ==1, 0, 1]]; then t(i,j)=If[Sum[b[i, k]*b[j, k], {k, 0, n}] == 0, 1, 0]. 1
1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0 (list; table; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Row sums are: {1, 1, 1, 2, 2, 1, 2, 4, 4, 2, 1, 2, 4, 2, 4, 8, 8, ...}.

In this method the information is complete: as it is a symbol representation instead of {0,1}, {-1,1} or {1,2} can be used in the output just as well.

This kind of code is used in minimal coding representations like the binary Gray code.

FORMULA

c(i,k)=Floor[Mod[i/2^k, 2]]; b(i,k)=If[c[i, k] == 0 && c[i, k + 1] == 0, 0, If[c[ i, k] == 1 && c[i, k + 1] ==1, 0, 1]]; t(i,j)=If[Sum[b[i, k]*b[j, k], {k, 0, n}] == 0, 1, 0].

EXAMPLE

{1},

{1, 0},

{1, 0, 0},

{1, 1, 0, 0},

{1, 1, 0, 0, 0},

{1, 0, 0, 0, 0, 0},

{1, 0, 0, 1, 0, 0, 0},

{1, 1, 1, 1, 0, 0, 0, 0},

{1, 1, 1, 1, 0, 0, 0, 0, 0},

{1, 0, 0, 1, 0, 0, 0, 0, 0, 0},

{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},

{1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},

{1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0},

{1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0},

{1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0},

{1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0},

{1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0}

MATHEMATICA

Clear[c, b, n, a0, d] c[i_, k_] := Floor[Mod[i/2^k, 2]]; b[i_, k_] = If[c[i, k] == 0 && c[i, k + 1] == 0, 0, If[c[ i, k] == 1 && c[i, k + 1] == 1, 0, 1]]; n = 16; a0 = Table[Table[If[Sum[b[i, k]*b[j, k], {k, 0, n}] == 0, 1, 0], {j, 0, i}], {i, 0, n}]; Flatten[a0]

CROSSREFS

Cf. A131218.

Sequence in context: A176918 A176890 A164057 * A167501 A185175 A147612

Adjacent sequences:  A140817 A140818 A140819 * A140821 A140822 A140823

KEYWORD

nonn,tabl

AUTHOR

Roger L. Bagula and Gary W. Adamson (rlbagulatftn(AT)yahoo.com), Oct 17 2008

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 17 02:48 EST 2012. Contains 205978 sequences.