Search: id:A046196 Results 1-1 of 1 results found. %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, Link to a section of The World of Mathematics. %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) Search completed in 0.001 seconds