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 A085737 Numerators in triangle formed from Bernoulli numbers. 13
 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, -1, 1, 2, 1, -1, 0, -1, 1, 1, -1, 0, 1, -1, -1, 8, -1, -1, 1, 0, 1, -1, 4, 4, -1, 1, 0, -1, 1, -1, -4, 8, -4, -1, 1, -1, 0, -1, 1, -8, 4, 4, -8, 1, -1, 0, 5, -5, 7, 4, -116, 32, -116, 4, 7, -5, 5, 0, 5, -5, 32, -28, 16, 16, -28, 32, -5, 5, 0 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,13 COMMENTS Triangle is determined by rules 0) the top number is 1; 1) each number is the sum of the two below it; 2) it is left-right symmetric; 3) the numbers in each of the border rows, after the first 3, are alternately 0. Up to signs this is the difference table of the Bernoulli numbers (see A212196). The Sage script below is based on L. Seidel's algorithm and does not make use of a library function for the Bernoulli numbers; in fact it generates the Bernoulli numbers on the fly. - Peter Luschny, May 04 2012 REFERENCES Ludwig Seidel, Über eine einfache Entstehungsweise der Bernoulli'schen Zahlen und einiger verwandten Reihen, Sitzungsberichte der mathematisch-physikalischen Classe der königlich bayerischen Akademie der Wissenschaften zu München, volume 7 (1877), 157-187. [From Peter Luschny, May 04 2012] LINKS Fabien Lange and Michel Grabisch, The interaction transform for functions on lattices Discrete Math. 309 (2009), no. 12, 4037-4048. [From N. J. A. Sloane, Nov 26 2011] Peter Luschny, The computation and asymptotics of the Bernoulli numbers. FORMULA T(n, 0) = (-1)^n*Bernoulli(n), T(n, k) = T(n-1, k-1) - T(n, k-1) for k=1..n. T(n,k) = Sum_{j=0..k} binomial(k,j)*Bernoulli(n-j). [Lange and Grabisch] EXAMPLE Triangle of fractions begins     1;    1/2,   1/2;    1/6,   1/3,   1/6;     0,    1/6,   1/6,     0;   -1/30,  1/30,  2/15,   1/30,  -1/30;     0,   -1/30,  1/15,   1/15,  -1/30,    0;    1/42, -1/42, -1/105,  8/105, -1/105, -1/42,   1/42;     0,    1/42, -1/21,   4/105,  4/105, -1/21,   1/42,   0;   -1/30,  1/30, -1/105, -4/105,  8/105, -4/105, -1/105, 1/30, -1/30; MAPLE nmax:=11; for n from 0 to nmax do T(n, 0):= (-1)^n*bernoulli(n) od: for n from 1 to nmax do for k from 1 to n do  T(n, k) := T(n-1, k-1) - T(n, k-1) od: od: for n from 0 to nmax do seq(T(n, k), k=0..n) od: seq(seq(numer(T(n, k)), k=0..n), n=0..nmax);  # Johannes W. Meijer, Jun 29 2011, revised Nov 25 2012 MATHEMATICA t[n_, 0] := (-1)^n*BernoulliB[n]; t[n_, k_] := t[n, k] = t[n-1, k-1] - t[n, k-1]; Table[t[n, k] // Numerator, {n, 0, 11}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jan 07 2014 *) PROG (Sage) def BernoulliDifferenceTable(n) :     def T(S, a) :         R = [a]         for s in S :             a -= s             R.append(a)         return R     def M(A, p) :         R = T(A, 0)         S = add(r for r in R)         return -S / (2*p+3)     R = [1/1]     A = [1/2, -1/2]; R.extend(A)     for k in (0..n-2) :         A = T(A, M(A, k)); R.extend(A)         A = T(A, 0); R.extend(A)     return R def A085737_list(n) : return map(numerator, BernoulliDifferenceTable(n)) # Peter Luschny, May 04 2012 CROSSREFS Cf. A085738, A212196. See A051714/A051715 for another triangle that generates the Bernoulli numbers. Sequence in context: A261447 A287325 A286133 * A191904 A265892 A324966 Adjacent sequences:  A085734 A085735 A085736 * A085738 A085739 A085740 KEYWORD sign,frac,tabl AUTHOR N. J. A. Sloane, following a suggestion of J. H. Conway, Jul 23 2003 EXTENSIONS Sign flipped in formula by Johannes W. Meijer, Jun 29 2011 STATUS approved

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Last modified August 20 05:25 EDT 2019. Contains 326139 sequences. (Running on oeis4.)