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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 G. C. Greubel, Table of n, a(n) for n = 0..500 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 Cf. A104967, A104969. Sequence in context: A285103 A123258 A278227 * A286894 A346911 A225187 Adjacent sequences:  A104965 A104966 A104967 * A104969 A104970 A104971 KEYWORD nonn AUTHOR Paul D. Hanna, Mar 30 2005 STATUS approved

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Last modified November 27 12:51 EST 2021. Contains 349394 sequences. (Running on oeis4.)