非歐拉商數

喺數論中，非歐拉商數係一個唔喺歐拉函數 φ 值域中嘅整數n 。換句話講，若果n係非歐拉商數，就唔存在一個整數x，咁啱有n 個小於x 而又同x 互質嘅整數。除咗1 之外（x=1 同x=2 都係佢嘅解），其他嘅奇數都係非歐拉商數。頭五十個偶非歐拉商數為：

14, 26, 34, 38, 50, 62, 68, 74, 76, 86, 90, 94, 98, 114, 118, 122, 124, 134, 142, 146, 152, 154, 158, 170, 174, 182, 186, 188, 194, 202, 206, 214, 218, 230, 234, 236, 242, 244, 246, 248, 254, 258, 266, 274, 278, 284, 286, 290, 298, 302 （OEIS數列A005277）

偶非歐拉商數可能比某一質數多一，但絕不可能少一，因為所有小於某一質數嘅數，依定義，必定同呢個質數互質。寫成方程式，即係φ(p) = p − 1 。此外，普洛尼克數 p(p − 1) 亦絕對唔會係非歐拉商數，因為φ(p ²) = p(p − 1) 。

更甚者，非歐拉商數亦唔會係$(p-1)p^{n}$型嘅數，因爲$\varphi (p^{n+1})=(p-1)p^{n}$。

表

n	k 使得 φ(k) = n	n	k 使得 φ(k) = n	n	k 使得 φ(k) = n	n	k 使得 φ(k) = n
1	1, 2	37		73		109
2	3, 4, 6	38		74		110	121, 242
3		39		75		111
4	5, 8, 10, 12	40	41, 55, 75, 82, 88, 100, 110, 132, 150	76		112	113, 145, 226, 232, 290, 348
5		41		77		113
6	7, 9, 14, 18	42	43, 49, 86, 98	78	79, 158	114
7		43		79		115
8	15, 16, 20, 24, 30	44	69, 92, 138	80	123, 164, 165, 176, 200, 220, 246, 264, 300, 330	116	177, 236, 354
9		45		81		117
10	11, 22	46	47, 94	82	83, 166	118
11		47		83		119
12	13, 21, 26, 28, 36, 42	48	65, 104, 105, 112, 130, 140, 144, 156, 168, 180, 210	84	129, 147, 172, 196, 258, 294	120	143, 155, 175, 183, 225, 231, 244, 248, 286, 308, 310, 350, 366, 372, 396, 450, 462
13		49		85		121
14		50		86		122
15		51		87		123
16	17, 32, 34, 40, 48, 60	52	53, 106	88	89, 115, 178, 184, 230, 276	124
17		53		89		125
18	19, 27, 38, 54	54	81, 162	90		126	127, 254
19		55		91		127
20	25, 33, 44, 50, 66	56	87, 116, 174	92	141, 188, 282	128	255, 256, 272, 320, 340, 384, 408, 480, 510
21		57		93		129
22	23, 46	58	59, 118	94		130	131, 262
23		59		95		131
24	35, 39, 45, 52, 56, 70, 72, 78, 84, 90	60	61, 77, 93, 99, 122, 124, 154, 186, 198	96	97, 119, 153, 194, 195, 208, 224, 238, 260, 280, 288, 306, 312, 336, 360, 390, 420	132	161, 201, 207, 268, 322, 402, 414
25		61		97		133
26		62		98		134
27		63		99		135
28	29, 58	64	85, 128, 136, 160, 170, 192, 204, 240	100	101, 125, 202, 250	136	137, 274
29		65		101		137
30	31, 62	66	67, 134	102	103, 206	138	139, 278
31		67		103		139
32	51, 64, 68, 80, 96, 102, 120	68		104	159, 212, 318	140	213, 284, 426
33		69		105		141
34		70	71, 142	106	107, 214	142
35		71		107		143
36	37, 57, 63, 74, 76, 108, 114, 126	72	73, 91, 95, 111, 117, 135, 146, 148, 152, 182, 190, 216, 222, 228, 234, 252, 270	108	109, 133, 171, 189, 218, 266, 324, 342, 378	144	185, 219, 273, 285, 292, 296, 304, 315, 364, 370, 380, 432, 438, 444, 456, 468, 504, 540, 546, 570, 630

參考

• L. Havelock, A Few Observations on Totient and Cototient Valence.pdf A Few Observations on Totient and Cototient Valence from PlanetMath

睇埋

• 非互補歐拉商數