Question

Continua sirul:2,3,5,8,12,17,23,...Ce numar se afla pe locul 100???

Answer 1

2=2
2+1=3=1+2
3+2=5=1+2+2=2*3/2+2
5+3=8=1+2+2+3=3*4/2+2
8+4=12=1+2+2+3+4=4*5/2+2
12+5=17=1+2+2+3+4+5=5*6/2+2
17+6=23=1+2+2+3+4+5+6=6*7/2+2


23+7=30=1+2+2+3+4+5+6+7=7*8/2+2
30+8=38=1+2+2+3+4+5+6+7+8=8*9/2+2
38+9=47=1+2+2+3+4+5+6+7+8+9=9*10/2+2
47+10=57=1+2+2+3+4+5+6+7+8+9+10=10*11/2+2

al 100-lea termen=99*100/2+2=9900/2=2=4950+2=4952