Question

ce nr lipsestie din următorul sir
1,2,4,7,?,16​

Answer 1

Răspuns:

numărul care lipsește este 11

Explicatie:

A(1)=1=1

A(1)=1=1A(2)=A(1)+1=2

A(1)=1=1A(2)=A(1)+1=2A(3)=A(2)+2=A(1)+3=4

A(1)=1=1A(2)=A(1)+1=2A(3)=A(2)+2=A(1)+3=4A(4)=A(3)+4-1=A(1)+3+3=7

A(1)=1=1A(2)=A(1)+1=2A(3)=A(2)+2=A(1)+3=4A(4)=A(3)+4-1=A(1)+3+3=7A(5)=A(4)+5-1=A(1)+6+4=11