1+2+3=6

1+2+3+4+5+6+7+8+9+10

+11=66

1+2+3+4+5+6+7+8+9+10

+11+12+13+14+15+16+17

+18+19+20+21+22+23+24

+25+26+27+28+29+30+31

+32+33+34+35+36=666