%I A046196
%S A046196 1,9,77,1519,12987,111035,2190397,18727245,160112393,3158550955,
%T A046196 27004674303,230881959671,4554628286713,38940721617681,
%U A046196 332931625733189,6567770830889191,56152493568021699
%N A046196 Indices of square numbers which are also heptagonal.
%H A046196 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               HeptagonalSquareNumber.html">Link to a section of The World of Mathematics.</
               a>
%F A046196 Contribution from Weisenhorn Paul (paulweisenhorn(AT)online.de), May 
               01 2009: (Start)
%F A046196 a(n+6)=1442*a(n+3)-a(n) with
%F A046196 a(-2)=-77; a(-1)=-9; a(0)=-1; a(1)=1; a(2)=9; a(3)=77;
%F A046196 A=(721+sqrt(10)*228)^k; B=(721-sqrt(10)*228)^k;
%F A046196 a(3*k+1)=(7*(A-B)/sqrt(10)+2*(A+B))/4;
%F A046196 a(3*k+2)=(57*(A-B)/sqrt(10)+18*(A+B))/4;
%F A046196 a(3*k)=(7*(A-B)/sqrt(10)-2*(A+B))/4;
%F A046196 (End)
%p A046196 Contribution from Weisenhorn Paul (paulweisenhorn(AT)online.de), May 
               01 2009: (Start)
%p A046196 for n from 1 to 10000 do m:=sqrt((5*n*n-3*n)/2):
%p A046196 if (trunc(m)=m) then print(n,m): end if: end do:
%p A046196 (End)
%Y A046196 Cf. A036354, A046195.
%Y A046196 A046196 [From Weisenhorn Paul (paulweisenhorn(AT)online.de), May 01 2009]
%Y A046196 Sequence in context: A046150 A124131 A000445 this_sequence A123918 A044577 
               A126632
%Y A046196 Adjacent sequences: A046193 A046194 A046195 this_sequence A046197 A046198 
               A046199
%K A046196 nonn
%O A046196 1,2
%A A046196 Eric Weisstein (eric(AT)weisstein.com)