Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #7 May 24 2012 05:14:56
%S 0,3,12,105,168,444,603,1158,2550,3060,5469,7518,8568,11292,16563,
%T 23217,25458,34167,40740,43998,56307,65391,81210,106272,120000,126750,
%U 142155,149685,166863,241152
%N An eighth of the product of three integers surrounding the (n+1)-st prime, minus half of the product of the 3 numbers surrounding n+1.
%H Harvey P. Dale, <a href="/A141535/b141535.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) = A127917(n+1)/8-A027480(n) = {p(n+1)-1}*p(n+1)*{p(n+1)+1}/8-n(n+1)(n+2)/2.
%p A127917 := proc(n) p := ithprime(n) ; (p-1)*p*(p+1) ; end: A027480 := proc(n) n*(n+1)*(n+2)/2 ; end: A := proc(n) A127917(n+1)/8-A027480(n) ; end: for n from 1 to 40 do printf("%d,",A(n)) ; od: # _R. J. Mathar_, Aug 20 2008
%t a[n_] = (Prime[n + 1] - 1)*Prime[n + 1]*(Prime[n + 1] + 1)/8 - n*(n + 1)*(n + 2)/2; Table[a[n], {n, 1, 30}]
%t f[n_]:=Module[{pr=Prime[n+1],n1=n+1},(pr(pr^2-1))/8-(n1(n1^2-1))/2]; Array[f,30] (* _Harvey P. Dale_, May 24 2012 *)
%K nonn
%O 1,2
%A _Roger L. Bagula_, Aug 12 2008
%E Edited by _N. J. A. Sloane_, Aug 23 2008