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A115218 Triangle read by rows: zeroth row is 0; to get row n >= 1, append next 2^n numbers to end of previous row. 1
0, 0, 1, 2, 0, 1, 2, 3, 4, 5, 6, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Robert Israel, Table of n, a(n) for n = 0..10000

FORMULA

From Robert Israel, Jan 02 2018: (Start)

G.f.: x^2/(1-x)^2 - (1-x)^(-1)*Sum_{n>=2} (2^n-1)*x^(2^(n+1)-n-2).

a(n) = k if n = 2^m - m + k - 1, 0 <= k <= 2^m-2.

G.f. as triangle: (1-y)^(-2)*Sum_{n>=1} x^n*(y + (1-2^n)*y^(2^n-1)+(2^n-2)*y^(2^n)). (End)

EXAMPLE

Triangle begins:

0

0 1 2

0 1 2 3 4 5 6

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

...

MAPLE

seq($0..2^n-2, n=0..5); # Robert Israel, Jan 02 2018

CROSSREFS

Cf. A126646 (length of n-th row).

Sequence in context: A238794 A135317 A227179 * A023858 A011118 A304784

Adjacent sequences:  A115215 A115216 A115217 * A115219 A115220 A115221

KEYWORD

nonn,tabf

AUTHOR

N. J. A. Sloane, based on a suggestion from Harrie Grondijs, Mar 04 2006

STATUS

approved

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Last modified May 19 15:15 EDT 2019. Contains 323395 sequences. (Running on oeis4.)