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 A168426 Square array of denominators of a truncated array of Bernoulli twin numbers (A168516), read by antidiagonals. 1
 3, 6, 6, 30, 15, 30, 30, 15, 15, 30, 42, 105, 105, 105, 42, 42, 21, 105, 105, 21, 42, 30, 105, 105, 105, 105, 105, 30, 30, 15, 105, 105, 105, 105, 15, 30, 66, 165, 165, 1155, 231, 1155, 165, 165, 66, 66, 33, 165, 165, 231, 231, 165, 165, 33, 66, 2730, 15015, 15015, 15015, 15015, 15015, 15015, 15015 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Entries are multiples of 3. The sequence of fractions A051716()/A051717() is a sequence of first differences of A164555()/A027642(). LINKS MATHEMATICA max = 11; c[0] = 1; c[n_?EvenQ] := BernoulliB[n] + BernoulliB[n-1]; c[n_?OddQ] := -BernoulliB[n] - BernoulliB[n-1]; cc = Table[c[n], {n, 0, max+1}]; diff = Drop[#, 2]& /@ Table[ Differences[cc, n], {n, 0, max-1}]; Flatten[ Table[ diff[[n-k+1, k]], {n, 1, max}, {k, 1, n}]] // Denominator (* Jean-François Alcover_, Aug 09 2012 *) CROSSREFS Cf. A085738, A085737. Sequence in context: A103463 A223048 A181372 * A065931 A137497 A032338 Adjacent sequences:  A168423 A168424 A168425 * A168427 A168428 A168429 KEYWORD nonn,tabl,frac AUTHOR Paul Curtz, Nov 25 2009 EXTENSIONS More terms from R. J. Mathar, Jul 10 2011 STATUS approved

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Last modified May 19 01:48 EDT 2013. Contains 225428 sequences.