ぃの计

计厩產稲焊疭 (Paul Erdos 1913-1996)

(酚The MacTutor History of Mathematics Achievehttp://www-gap.dcs.st-and.ac.uk/~history/ )

 

и s(x) ボ计 x 痷羆㎝ (Sum of Aliquot Divisors) рぃ珹┮Τ癬ㄓ

┏硂 s(x) 氮穦琌ぐ或计㎡穦ぃ穦Τㄇ俱计 n ㄏ s(x)=n 礚秆㎡

计厩產稲焊疭 (Paul Erdos 1913-1996) 谍礚计 n ㄏ s(x)=n 礚秆и嘿硂ㄇ计ぃの计 (Untouchable Number) 1000 ぃの计

2 5 52 88 96 120 124 146 162 188 206 210 216 246 248 262 268 276 288 290 292 304 322 324 326 342 372 406 408 426 430 448 472 474 498 516 518 520 530 540 552 556 562 576 584 612 624 626 628 658 668 670 714 718 726 732 738 748 750 756 766 768 782 784 792 802 804 818 836 848 852 872 892 894 896 898 902 916 926 936 964 966 976 982 996 ...

(OEIS A005114)

璝紈ぺ划瞦稱 (Goldbach Conjecture) 琌タ絋杠 5 獽琌暴ぃの计硂妓┮Τぃ 6 案计 ( Even Number) 糶Θㄢ计㎝玥ヴぃぶ 7 计だ╊Θㄢ计㎝ 1  2n+1 = p+q+1иσ納俱计 pqs(pq) = p+q+1 = 2n+1硂縒ミ谍㎡

и临祇瞷ㄇパぃの计舱Θ衡砃计 (Arithmetic Progression)322 324 326 ㎝ 916 926 936单穦ヴ衡砃计㎡ぃの计丁回┏穦Τ㎡

计產临祇瞷ぃの计だ薄猵

俱计
ぃの计计
10
2
100
5
1000
89
10000
1212

┏ぃの计计琌耎床籔

硂琌ゼ秆ぇ良痙產秨祇

 

把σゅ膍の呼

Guy, R. K. "Untouchable Numbers." ”B10 in Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, pp. 66-67, 1994.

Weisstein, E. M. "Untouchable Number." From MathWorld. http://mathworld.wolfram.com/UntouchableNumber.html.

Wells, D. The Penguin Dictionary of Curious and Interesting Numbers. Middlesex, England: Penguin Books, p. 60, 1986.

 

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