

A098832


Square array read by antidiagonals: evennumbered rows of the table are of the form n*(n+m) and oddnumbered rows are of the form n*(n+m)/2.


5



1, 3, 3, 6, 8, 2, 10, 15, 5, 5, 15, 24, 9, 12, 3, 21, 35, 14, 21, 7, 7, 28, 48, 20, 32, 12, 16, 4, 36, 63, 27, 45, 18, 27, 9, 9, 45, 80, 35, 60, 25, 40, 15, 20, 5, 99, 44, 77, 33, 55, 22, 33, 11, 54, 96, 42, 72, 30, 48, 18, 117, 52, 91, 39, 65, 26, 63, 112, 49, 84, 35, 135, 60, 105
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OFFSET

1,2


COMMENTS

The rows of this table and that in A098737 are related. Given a function f = n/(1+(1+n)mod(2)), row n of A098737 can be derived from row n of T by multiplying the latter by f(n); row n of T can be derived from row n of A098737 by dividing the latter by f(n).


LINKS

Table of n, a(n) for n=1..74.


FORMULA

Item m of row n of T is given (in infix form) by: n T m = n * (n + m) / (1 + m (mod 2)). E.g. Item 4 of row 3 of T: 3 T 4 = 14.


EXAMPLE

Array begins:
1 3 6 10 15
3 8 15 24 35
2 5 9 14 20
5 12 21 32 45
3 7 12 18 25


CROSSREFS

Rows 1 through 9 are A000217, A005563, A000096, A028347, A027379, A028560, A055999, A028566, A056000. Rows 10 through 19 are A098603, A056115, A098847, A056119, A098848, A056121, A098849, A056126, A098850, A051942. Columns 1 and 2 are A026741, A022998.
Sequence in context: A050065 A298732 A078477 * A107985 A114999 A160733
Adjacent sequences: A098829 A098830 A098831 * A098833 A098834 A098835


KEYWORD

easy,nonn,tabl


AUTHOR

Eugene McDonnell (eemcd(AT)mac.com), Nov 02 2004


STATUS

approved



