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A104968 Absolute row sums of triangle A104967. 4
1, 2, 4, 6, 6, 12, 22, 32, 34, 52, 100, 150, 170, 266, 438, 640, 766, 1196, 1996, 2888, 3210, 4994, 8534, 12392, 15106, 22154, 34366, 52134, 62148, 96956, 156396, 217416, 262062, 394164, 643908, 950944, 1150368, 1689176, 2600992, 3767888, 4840338 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
a(n) = Sum_{k=0..n} abs(A104967(n,k)).
MATHEMATICA
A104967[n_, k_]:= A104967[n, k]= Sum[(-2)^j*Binomial[k+1, j]*Binomial[n-j, k], {j, 0, n-k}];
A104968[n_]:= A104968[n]= Sum[Abs[A104967[n, k]], {k, 0, n}];
Table[A104968[n], {n, 0, 50}] (* G. C. Greubel, Jun 09 2021 *)
PROG
(PARI) {a(n)=local(X=x+x*O(x^n)); sum(k=0, n, abs(polcoeff(polcoeff((1-2*X)/(1-X-X*y*(1-2*X)), n, x), k, y)))}
(Sage)
@cached_function
def A104967(n, k): return sum( (-2)^j*binomial(k+1, j)*binomial(n-j, k) for j in (0..n-k))
def A104968(n): return sum( abs(A104967(n, k)) for k in (0..n))
[A104968(n) for n in (0..50)] # G. C. Greubel, Jun 09 2021
CROSSREFS
Sequence in context: A285103 A123258 A278227 * A286894 A346911 A225187
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 30 2005
STATUS
approved

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Last modified March 29 10:59 EDT 2024. Contains 371277 sequences. (Running on oeis4.)