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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 MATHEMATICA Range[0, #-1]&/@Accumulate[2^Range[0, 5]]//Flatten (* Harvey P. Dale, Jan 20 2021 *) CROSSREFS Cf. A126646 (length of n-th row). Sequence in context: A135317 A332663 A227179 * A023858 A011118 A304784 Adjacent sequences:  A115215 A115216 A115217 * A115219 A115220 A115221 KEYWORD nonn,tabf,changed AUTHOR N. J. A. Sloane, based on a suggestion from Harrie Grondijs, Mar 04 2006 STATUS approved

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Last modified January 23 16:36 EST 2021. Contains 340385 sequences. (Running on oeis4.)