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A082693 Pyramidal sequence built with powers of 2. 3
1, 2, 1, 2, 4, 2, 1, 2, 4, 8, 4, 2, 1, 2, 4, 8, 16, 8, 4, 2, 1, 2, 4, 8, 16, 32, 16, 8, 4, 2, 1, 2, 4, 8, 16, 32, 64, 32, 16, 8, 4, 2, 1, 2, 4, 8, 16, 32, 64, 128, 64, 32, 16, 8, 4, 2, 1, 2, 4, 8, 16, 32, 64, 128, 256, 128, 64, 32, 16, 8, 4, 2, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 256, 128 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..84.

EXAMPLE

Triangle begins:

                                 1

                               2 1 2

                             4 2 1 2 4

                           8 4 2 1 2 4 8

                        16 8 4 2 1 2 4 8 16

                     32 16 8 4 2 1 2 4 8 16 32

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

              128 64 32 16 8 4 2 1 2 4 8 16 32 64 128

          256 128 64 32 16 8 4 2 1 2 4 8 16 32 64 128 256

      512 256 128 64 32 16 8 4 2 1 2 4 8 16 32 64 128 256 512

1024 512 256 128 64 32 16 8 4 2 1 2 4 8 16 32 64 128 256 512 1024

... - Philippe Deléham, Mar 20 2013

MATHEMATICA

pow2Pyram[row_] := Module[{st = 2^Range[0, row]}, Join[st, Reverse[Most[Rest[st]]]]]; Flatten[Array[pow2Pyram, 10]] (* Harvey P. Dale, May 09 2012 *)

Flatten[Table[Table[2^Abs[col], {col, -row, row}], {row, 0, 7}]] (* Alonso del Arte, Apr 15 2017 *)

PROG

(PARI) for(i=0, 9, forstep(j=i, 0, -1, print1(1<<j", ")); for(j=1, i, print1(1<<j", "))) \\ Charles R Greathouse IV, Mar 20 2013

CROSSREFS

Cf. A004738, A082693 (partial sums), A036563 (row sums).

Sequence in context: A186187 A013943 A164281 * A225081 A307368 A097082

Adjacent sequences:  A082690 A082691 A082692 * A082694 A082695 A082696

KEYWORD

nonn,tabf,easy

AUTHOR

Benoit Cloitre, Apr 12 2003

STATUS

approved

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Last modified June 18 04:41 EDT 2021. Contains 345098 sequences. (Running on oeis4.)