5 9 13 20 29 40 53 12+4 = 1+4 = 5 22+4 = 4+4 = 8 <-- 2nd term should have been 8, not 9 32+4 = 9+5 = 14 42+4 = 16+4 = 20 52+4 = 25+4 = 29 62+4 = 36+4 = 40 72+4 = 49+4 = 53 So the second term should be 8, not 9. It must have been a typo. All the terms but the 2nd one fit the pattern of an = n2+4. Edwin