If Sn= nC02+ nC12+ nC32+…+ nCn2, then maximum value of Sn+1Sn is _________.
(where [.] denotes the greatest integer function)
Sn=2nCn
⇒ Sn+1Sn= 2n+2Cn+12ncn=(2n+2)(2n+1)(n+1)(n+1)=2(2n+1)n+1=4−2n+1
∴ Sn+1Snmax=3