设数列{An}是不能写成3个平方数之和的正整数数列:
007, 015, 023, 028, 031, 039, 047, 055, 060, 063, 071, 079, 087, 092, 095, 103, 111, 112, 119, 124, 127,
135, 143, 151, 156, 159, 167, 175, 183, 188, 191, 199, 207, 215, 220, 223, 231, 239, 240, 247, 252, 255,
263, 271, 279, 284, 287, 295, 303, 311, 316, 319, 327, 335, 343, 348, 351, 359, 367, 368, 375, 380, 383,
391, 399, 407, 412, 415, 423, 431, 439, 444, 447, 448, 455, 463, 471, 476, 479, 487, 495, 496, ............
我找了个粗糙的节点通项,渴望能引出细腻的通项公式。谢谢大家!
\(a(\frac{7×4^n-4}{6})=7×4^n\)
,譬如:
a(4)=28
a(18)=112
a(74)=448
a(298)=1792
a(1194)=7168
a(4778)=28672
a(19114)=114688
a(76458)=458752
a(305834)=1835008 |