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A110769 The r-th term of the n-th row of the following triangle contains sum of r successive numbers in decreasing order beginning from T(n)-T(r-1) where T(n) is the n-th triangular number. 1 3 3 6 9 6 10 17 18 10 15 27 33 30 15 ... Sequence contains the triangle by rows. 4
1, 3, 3, 6, 9, 6, 10, 17, 18, 10, 15, 27, 33, 30, 15, 21, 39, 51, 54, 45, 21, 28, 53, 72, 82, 80, 63, 28, 36, 69, 96, 114, 120, 111, 84, 36, 45, 87, 123, 150, 165, 165, 147, 108, 45, 55, 107, 153, 190, 215, 225, 217, 188, 135, 55, 66, 129, 186, 234, 270, 291, 294, 276 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The first term in the n-th row is T(n) and the n-th term also is T(n). - Joshua Zucker, Dec 14 2005

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

For n = 4 the terms of the 4th row are 10, 9+8, 7+6+5, 4+3+2+1.

MATHEMATICA

Table[Total/@TakeList[Range[(n(n+1))/2, 1, -1], Range[n]], {n, 20}]//Flatten (* Requires Mathematica version 11 or later *) (* Harvey P. Dale, Jul 08 2018 *)

CROSSREFS

Cf. A110768.

Sequence in context: A205970 A104715 A164743 * A093445 A098358 A136289

Adjacent sequences:  A110766 A110767 A110768 * A110770 A110771 A110772

KEYWORD

easy,tabl,nonn

AUTHOR

Amarnath Murthy, Aug 12 2005

EXTENSIONS

Corrected and extended by Joshua Zucker, Dec 14 2005

STATUS

approved

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Last modified May 6 05:18 EDT 2021. Contains 343580 sequences. (Running on oeis4.)