A140643 - OEIS

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A140643

First differences of A140642.

1, 1, 1, 1, 1, 2, 2, 1, 1, 4, 4, 1, 1, 2, 8, 8, 2, 1, 1, 4, 16, 16, 4, 1, 1, 2, 8, 32, 32, 8, 2, 1, 1, 4, 16, 64, 64, 16, 4, 1

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,6

COMMENTS

(*) Main diagonal = A011782 but vertical = 1, A011782 unknown.

LINKS

Table of n, a(n) for n=0..39.

FORMULA

Also a triangle on line (*): 1; 1, 1; 1, 1, 2; 2, 1, 1, 4; 4, 1, 1, 2, 8; 8, 2, 1, 1, 4, 16; 16, 4, 1, 1, 2, 8, 32; 32, 8, 2, 1, 1, 4, 16, 64; Row sums:1, 2, 4, 8, 16 =A000079(n). Note even palindromes finishing a row and beginning next one.

MATHEMATICA

maxTerm = 384; FixedPoint[(nMax++; Print["nMax = ", nMax]; jj = Table[(2^n - (-1)^n)/3, {n, 0, nMax}]; Table[Differences[jj, n], {n, 0, nMax}] // Flatten // Abs // Union // Select[#, 0 < # <= maxTerm &] &) &, nMax = 5 ] // Differences (* Jean-François Alcover, Dec 16 2014 *)

CROSSREFS

Sequence in context: A279863 A201757 A053390 * A331409 A108017 A293208

Adjacent sequences: A140640 A140641 A140642 * A140644 A140645 A140646

KEYWORD

nonn,uned

AUTHOR

Paul Curtz, Jul 08 2008

STATUS

approved