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A134237
Triangle read by rows, a(1) = 1, n-th row n terms of: (2n-1, 2n, 2n+1, ..., followed by n).
1
1, 3, 2, 5, 6, 3, 7, 8, 9, 4, 9, 10, 11, 12, 5, 11, 12, 13, 14, 15, 6, 13, 14, 15, 16, 17, 18, 7, 15, 16, 17, 18, 19, 20, 21, 8, 17, 18, 19, 20, 21, 22, 23, 24, 9, 19, 20, 21, 22, 23, 24, 25, 26, 27, 10, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 11, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 12
OFFSET
1,2
COMMENTS
Row sums = A134238: (1, 5, 14, 28, 47, 71, 100, 134, ...).
EXAMPLE
First few rows of the triangle:
1;
3, 2;
5, 6, 3;
7, 8, 9, 4;
9, 10, 11, 12, 5;
11, 12, 13, 14, 15, 6;
13, 14, 15, 16, 17, 18, 7;
...
PROG
(PARI) T(n, k) = if (k < n, (2*n-1) + (k-1), n);
tabl(nn) = for (n=1, nn, for (k=1, n, print1(T(n, k), ", ")); print); \\ Michel Marcus, Jul 13 2017
CROSSREFS
Cf. A134238.
Sequence in context: A338470 A262395 A198755 * A341521 A227192 A360260
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Oct 14 2007
EXTENSIONS
Corrected and extended by Michel Marcus, Jul 13 2017
STATUS
approved