A164984 - OEIS

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A164984

Odd (Jacobsthal) triangle

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

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,4

COMMENTS

Alternate diagonal sums give A008619.

Diagonals sums give A097076. - Philippe Deléham, Oct 13 2013

LINKS

Table of n, a(n) for n=1..55.

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

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

Cf. A164981, A001045, A005408, A015518 (row sums), A008619

Cf. A008288, A007318.

Sequence in context: A321785 A021755 A272295 * A248810 A339904 A208610

Adjacent sequences: A164981 A164982 A164983 * A164985 A164986 A164987

KEYWORD

nonn,tabl

AUTHOR

Mark Dols, Sep 03 2009, Sep 06 2009

STATUS

approved