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 A129765 Triangle, (1, 1, 2, 2, 2, ...) in every column. 2
 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Row sums = A004277, (1, 2, 4, 6, 8, 10, ...). Binomial transform of (1, 1, 2, 2, 2, ...) = A000325, starting (1, 2, 5, 12, 27, 58, ...). Binomial transform of A130196 = A130197, a triangle with row sums = the Cullen numbers, A002064. LINKS Table of n, a(n) for n=1..105. FORMULA Triangle, (1, 1, 2, 2, 2, ...) in every column. By rows, (1; 1, 1; 2, 1, 1; ...), continuing with (n-2) 2's followed by two 1's. Inverse of A000012 as an infinite lower triangular matrix (all 1's and the rest zeros), signed by columns: (+ - - + + - -, ...). EXAMPLE First few rows of the triangle: 1; 1, 1; 2, 1, 1; 2, 2, 1, 1; 2, 2, 2, 1, 1; ... MAPLE A129765 := proc(n, m) if abs(n-m)<2 then 1 ; else 2 ; end if ; end proc: for n from 1 to 18 do for m from 1 to n do printf("%d, ", A129765(n, m)) ; od ; od ; # R. J. Mathar, Jun 08 2007 MATHEMATICA Table[PadLeft[{1, 1}, n, 2], {n, 20}]//Flatten (* Harvey P. Dale, May 20 2019 *) CROSSREFS Cf. A004277, A002064, A000325, A130197. Sequence in context: A174886 A157415 A154325 * A143187 A348042 A143209 Adjacent sequences: A129762 A129763 A129764 * A129766 A129767 A129768 KEYWORD nonn,tabl,easy AUTHOR Gary W. Adamson, May 16 2007 EXTENSIONS More terms from R. J. Mathar, Jun 08 2007 STATUS approved

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Last modified February 29 10:50 EST 2024. Contains 370425 sequences. (Running on oeis4.)