This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A165908 Irregular triangle with the terms in the Staudt-Clausen theorem for the nonzero Bernoulli numbers multiplied by the product of the associated primes. 3

%I

%S 1,2,-1,6,-3,-2,30,-15,-10,-6,42,-21,-14,-6,30,-15,-10,-6,66,-33,-22,

%T -6,2730,-1365,-910,-546,-390,-210,12,-3,-2,-3060,-255,-170,-102,-30,

%U 44688,-399,-266,-114,-42

%N Irregular triangle with the terms in the Staudt-Clausen theorem for the nonzero Bernoulli numbers multiplied by the product of the associated primes.

%C The decomposition of a nonzero Bernoulli number in the Staudt-Clausen format is B(n) = A000146(n) - sum_k 1/A080092(n,k) with a set of primes A080092 characterising the right hand side.

%C If we multiply this equation by the product of the primes for a given n (which is in A002445), discard the left hand side, and list individually the terms associated with A000146 and each of the k, we get row n of the current triangle .

%e The decomposition of B_10 is 5/66 = 1-1/2-1/3-1/11. Multiplied by the product 2*3*11=66 of the denominators this becomes 5=66-33-22-6, and the 4 terms on the right hand side become one row of the table.

%e 1;

%e 2,-1;

%e 6,-3,-2;

%e 30,-15,-10,-6;

%e 42,-21,-14,-6;

%e 30,-15,-10,-6;

%e 66,-33,-22,-6;

%e 2730,-1365,-910,-546,-390,-210;

%p A165908 := proc(n) local i,p; Ld := [] ; pp := 1 ; for i from 1 do p := ithprime(i) ; if (2*n) mod (p-1) = 0 then Ld := [op(Ld),-1/p] ; pp := pp*p ; elif p-1 > 2*n then break; end if; end do: Ld := [A000146(n),op(Ld)] ; [seq(op(i,Ld)*pp,i=1..nops(Ld))] ; end proc: # for n>=2, R. J. Mathar, Jul 08 2011

%t a146[n_] := Sum[ Boole[ PrimeQ[d+1]]/(d+1), {d, Divisors[2n]}] + BernoulliB[2n]; primes[n_] := Select[ Prime /@ Range[n+1], Divisible[2n, #-1]& ]; row[n_] := With[{pp = primes[n]}, Join[{a146[n]}, -1/pp]*Times @@ pp]; Join[{1}, Flatten[ Table[row[n], {n, 0, 9}]]] (* Jean-François Alcover_, Aug 09 2012 *)

%Y Cf. A000146, A165884, A006954 (first column).

%K tabf,sign

%O 0,2

%A _Paul Curtz_, Sep 30 2009

%E Edited by R. J. Mathar, Jul 08 2011

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .