3,6,5,7,8,11,15,?

• answer is 22
  
  Working from left to right, add numbers first two together, and subtract 4, to give the next value along.
• 11 years agoHelpfull: Yes(19) No(7)
• Split the sequence into two: 3,5,8,15 and 6,7,11,?
  6+1^2=7
  7+2^2=11
  11+3^2=20
  so ans is 20
• 11 years agoHelpfull: Yes(5) No(6)
• 1+5=6,6+7=13,13+9=22 consecitive odd numbers
• 7 years agoHelpfull: Yes(0) No(2)
• if a_-1=0, and a_0=7 so that a_1=3, a_2=6, a_3=5, etc. then a_n = 2*a_(n-1) - a_(n-3) for n>1
• 7 years agoHelpfull: Yes(0) No(0)