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发表于 2022-12-18 11:45
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本帖最后由 yangchuanju 于 2022-12-18 11:47 编辑
几组涉素数阶乘p#的素数链
A115786给出分别加上一系列p#都是素数的最小素数。
A115786
Smallest prime number p such that p + 2#, p + 3#, ..., p + prime(n)# are all prime
3, 5, 11, 17, 41, 41, 41, 41, 86351, 86351, 235313357, 729457511, 99445156397, 818113387907, 7986903815771, 29065965967667
3+2=5,3+6=9;5是素数,9不是素数,素数链长等于2;
5+2=7,5+6=11,5+30=35;7和11是素数,35不是素数,素数链长等于3;……
41加2,6,30,210,2310,30030,510510,9699690都是素数,素数链长等于9;网页没有给出素数链长等于6-8的相关素数;
86351的素数链长等于11,……29065965967667的素数链长等于17。
A257467给出分别加上一系列p#的平方都是素数的最小素数。
A257467
Smallest prime number p such that p + psq(1), p + psq(2), ... p + psq(n) are all prime but p+psq(n+1) is not. (psq(n) is the square of the primorial.)
2, 3, 43, 7, 163, 397, 5527, 454543, 615883, 142516687, 68967673, 57502725253, 37520993053, 2630665498987, 39809897510563
3+2^2=7,3+6^2=39,7是素数,39不是素数,素数链长等于2;
43+2^2=47,43+6^2=79,43+30^2=943=23*41,素数链长等于3;……
素数39809897510563分别加上2#^2=4,3#^2=36,5#^2=900,……43#^2(43是第14号素数),是一个链长等于15的素数链。
A115785给出分别减去p#都是素数的最小素数。
A115785
Smallest prime number p such that p - p(1)#, p - p(2)#, ..., p - p(n)# are all prime
5, 13, 43, 229, 3463, 43789, 1088449, 19800379, 264333259, 9348884059, 228178314439, 7931712374479, 307867708410673, 13230211614496609, 618681508598750923
5-2=3,素数链长2;
13-2=11,13-6=7,素数链长3;
43-2=41,43-6=37,43-30=13,素数链长等于4;……
618681508598750923素数链长等于16。
A257466给出分别加上一系列p#的累加和都是素数的最小素数。
A257466
Smallest prime number p such that p + pps(1), p + pps(2), ..., p + pps(n) are all prime but p + pps(n+1) is not, where pps(n) is the partial primorial sum (A060389(n)).
2, 17, 11, 5, 3, 101, 19469, 38669, 191459, 191, 59, 3877889, 494272241, 360772331, 6004094833991, 41320119600341
17+2=19,17+2+6=23,17+2+6+30=55(不是素数),素数链长4;
11+2=13,11+2+6=19,11+2+6+30=53,11+2+6+30+210=263,素数链长5;……
For prime 3: 3+2, 3+8, 3+38, 3+248 are all prime. 3+2558 = 13 * 197 is not.
So a(4)= 3. (3 is the smallest prime that has exactly 4 terms.)
A258035给出分别加上一系列p#平方累加和都是素数的最小素数。
A258035
Smallest prime number p such that p + pssq(1), p + pssq(2), ... p + pssq(n) are all prime but p+pssq(n+1) is not, where pssq(n) is the partial sum of the square of the proper terms of the primorial (A189997(n)-1).
2, 37, 3, 7, 13, 277, 2617, 43, 2924263, 300999679, 631112173, 1368737917, 4428230508349
a(3) = 7 because 7 + 4, 7 + 40 and 7 + 940 are primes, but 7 + 45040 = 107 * 421 is not.
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