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A143971 Triangle read by rows, (3n-2) subsequences decrescendo 2
1, 4, 1, 7, 4, 1, 10, 7, 4, 1, 13, 10, 7, 4, 1, 16, 13, 10, 7, 4, 1, 19, 16, 13, 10, 7, 4, 1, 22, 19, 16, 13, 10, 7, 4, 1, 25, 22, 19, 16, 13, 10, 7, 4, 1, 28, 25, 22, 19, 16, 13, 10, 7, 4, 1, 31, 28, 25, 22, 19, 16, 13, 10, 7, 4, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Row sums = pentagonal numbers, A000326: (1, 5, 12, 22, 35,...).
The alternating row sums lead to A032766 and the antidiagonal sums to A006578. - Johannes W. Meijer, Sep 05 2013
LINKS
FORMULA
Triangle read by rows, (3n-2) subsequences decrescendo; 1<=k<=n.
(1, 4, 7, 10, 13,...) in every column.
T(n,k) = 3*n - 3*k + 1.
EXAMPLE
Triangle starts
1;
4, 1;
7, 4, 1;
10, 7, 4, 1;
...
MAPLE
T := (n, k) -> 3*n-3*k+1: seq(seq(T(n, k), k=1..n), n=1..11); # Johannes W. Meijer, Sep 05 2013
CROSSREFS
Sequence in context: A335619 A037022 A037023 * A367898 A016688 A143972
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Sep 06 2008
EXTENSIONS
Terms a(17) and a(38) corrected and terms added by Johannes W. Meijer, Sep 05 2013
STATUS
approved

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Last modified March 28 12:26 EDT 2024. Contains 371254 sequences. (Running on oeis4.)