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A219795 Sum of the absolute values of the antidiagonals of the triangle A135929(n) companion. See the comment. 3
2, 2, 2, 2, 3, 3, 5, 7, 10, 11, 16, 23, 33, 44, 58, 81, 114, 158, 212, 293, 407, 565, 777, 1064, 1471, 2036, 2813, 3863, 5334, 7370, 10183, 14046, 19356, 26726, 36909, 50955, 70251, 96977, 133886, 184841, 255092 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

The companion to A135929(n) is the triangle

2;

2, 0;

2, 0,  1;

2, 0, -1, 0;

2, 0, -3, 0, -1;

2, 0, -5, 0,  0, 0;

2, 0, -7, 0,  3, 0, 1;

2, 0, -9, 0,  8, 0, 1, 0;

(A192011(n) beginning with 2 instead of -1).

Consider a(1),a(5),a(10),a(14), that is, a(A193910(n) -1).

a(1)+a(4)-a(5) = 2, a(5)+a(8)-a(9) = 2, a(10)+a(13)-a(14) = 2, a(14)+a(17)-a(18) = 4, a(19)+a(22)-a(23) = 6, a(23)+a(26)-a(27) = 14, yields 2,2,2,4,6,14,24,60,... = 2*A047749(n) or 2, followed with A116637(n+1).

LINKS

Table of n, a(n) for n=0..40.

FORMULA

a(n) = sum abs ( [k=0..floor(n/2)] A192011(n-k,k) ), a(0)=2.

EXAMPLE

a(0)=2, a(1)=2, a(2)=2+0, a(3)=2+0, a(4)=2+0+1, a(5)=2+0+1.

MAPLE

A219795 := proc(n)

    if n=0 then

        2;

    else

        add(abs(A192011(n-k, k)), k=0..floor(n/2)) ;

    end if;

end proc: # R. J. Mathar, Jan 06 2013

CROSSREFS

Sequence in context: A285798 A321346 A291444 * A082602 A216644 A187758

Adjacent sequences:  A219792 A219793 A219794 * A219796 A219797 A219798

KEYWORD

nonn

AUTHOR

Paul Curtz, Nov 28 2012

EXTENSIONS

a(24)-a(40) from Jean-Francois Alcover, Nov 28 2012

STATUS

approved

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Last modified June 15 08:52 EDT 2021. Contains 345048 sequences. (Running on oeis4.)