1. positive integers
3. 1
5. False
7. True
9. a1=1, a2=4, a3=7, a4=10
11. a1=0, a2=12, a3=23, a4=34
13. a1=−1, a2=−4, a3=−9, a4=−16
15. a1=1, a2=43, a3=32, a4=85
17. a1=1, a2=−1, a3=1, a4=−1
19. a1=52, a2=114, a3=238, a4=4716
21. a1=0.6, a2=0.6, a3=0.6, a4=0.6
23. a1=−1, a2=12, a3=−16, a4=124
25. a1=−13, a2=19, a3=−127, a4=181
27. a1=e2, a2=e24, a3=e36, a4=e48
29.
31.
33.
35.
37.
39. an=3n−2
41. an=1n+1
43. an=(−1)n−1(2)
45. an=3n−12n
47. an=n(n+1)
49. an=2−(−1)nn+1
51. an=3n+1n+1
53. a1=2, a2=5, a3=8, a4=11, a5=14
55. a1=3, a2=6, a3=12, a4=24, a5=48
57. a1=7, a2=−11, a3= 25, a4=−47, a5=97
59. a1=2, a2=12, a3=2, a4=12, a5=2
61. a1=25, a2=−1125, a3=−25, a4=1125, a5=25
63.
2, 11, 26, 47, 74, 107, 146, 191, 242, 299
65.
0, 1, 2, 3, 4, 5, 6, 7, 8, 9
67.
0.5,−1, 2, 0.5,−1, 2, 0.5,−1, 2, 0.5
69. 120
71. 12
73. 1n+1
75. 2n+1
77. 35
79. 55
81. 25
83. 853140
85. 183
87. −118
89. ∑k=151(2k−1)
91. ∑k=11115k
93. ∑k=150(−1)k+1k
95. ∑k=110 kk+1
97. 4620
99. −1.345 (rounded to three decimal places)
101. 50