Search: id:A101686 Results 1-1 of 1 results found. %I A101686 %S A101686 1,2,10,100,1700,44200,1635400,81770000,5315050000,435834100000, %T A101686 44019244100000,5370347780200000,778700428129000000, %U A101686 132379072781930000000,26078677338040210000000 %N A101686 Sum of all coefficients in Prod[k=0..n, x+k^2 ]. %C A101686 Row sums of triangle of central factorial numbers (A008955). %C A101686 "HANOWA" is a matrix whose eigenvalues lie on a vertical line. It is an N X N matrix with 2 X 2 blocks with identity matrices in the upper left and lower right blocks and diagonal matrices containing the first N integers in the upper right and lower left blocks. In Matlab, the following code generates the sequence... for n=0:2:TERMS*2 det(gallery('hanowa', n)) end - Paul M. Payton (paul.payton(AT)lmco.com), Mar 31 2005 %C A101686 Cilleruelo shows that a(n) is a square only for n =0 and 3. - Charles R Greathouse IV, Aug 27 2008 %D A101686 Javier Cilleruelo, "Squares in (1^2+1)...(n^2+1)", Journal of Number Theory 128:8 (2008), pp. 2488-2491. %H A101686 Charles R Greathouse IV, Home Page [in lieu of email address] %p A101686 with (combinat):a:=n->mul(fibonacci(3,i), i=0..n):seq(a(n), n=0..14); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 25 2008 %o A101686 (PARI) a(n)=prod(k=1,n,k^2+1) - Charles R Greathouse IV, Aug 27 2008 %Y A101686 Equals 2 * A051893(n-1), n>0. %Y A101686 Sequence in context: A098279 A099826 A063959 this_sequence A074109 A036336 A070842 %Y A101686 Adjacent sequences: A101683 A101684 A101685 this_sequence A101687 A101688 A101689 %K A101686 nonn %O A101686 0,2 %A A101686 Ralf Stephan, Dec 13 2004 %E A101686 More terms from Charles R Greathouse IV, Aug 27 2008 Search completed in 0.001 seconds