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A164984
Odd (Jacobsthal) triangle
1
1, 1, 1, 3, 3, 1, 5, 9, 5, 1, 11, 23, 19, 7, 1, 21, 57, 61, 33, 9, 1, 43, 135, 179, 127, 51, 11, 1, 85, 313, 493, 433, 229, 73, 13, 1, 171, 711, 1299, 1359, 891, 375, 99, 15, 1, 341, 1593, 3309, 4017, 3141, 1641, 573, 129, 17, 1
OFFSET
1,4
COMMENTS
Alternate diagonal sums give A008619.
Diagonals sums give A097076. - Philippe Deléham, Oct 13 2013
FORMULA
Excel formula: C6=2*C4+C5+B5+B4 with C5=a(1)=1 and C6=a(2)
T(n,k) = T(n-1,k) + T(n-1,k-1) + 2*T(n-2,k) + T(n-2,k-1). - Philippe Deléham, Oct 13 2013
EXAMPLE
1
1,1
3,3,1
5,9,5,1
11,23,19,7,1
21,57,61,33,9,1
Pascal-like triangle based on a right-triangular sum (with the top multiplied by 2): For n=13 a(13)=2*a(3)+a(5)+a(8)+a(9)= 2+3+9+5=19.
CROSSREFS
Sequence in context: A321785 A021755 A272295 * A248810 A339904 A208610
KEYWORD
nonn,tabl
AUTHOR
Mark Dols, Sep 03 2009, Sep 06 2009
STATUS
approved