14/06/14 22:24:22.48
>>390
a_n=[√2×n]
1, 2, 4, 5, 7, 8, 9, 11, 12, 14, 15, 16, 18, 19, 21, 22, 24, 25, 26, 28, 29, 31, 32, 33, 35, …
a_nに現れない自然数を順にb_nとする
3, 6, 10, 13, 17, 20, 23, 27, 30, 34, …
b_n-a_nは
2, 4, 6, 8, 10, 12, 14, 16, 18, 20, …
どうして偶数の列になるのか？