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Search: id:A080185
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| A080185 |
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Primes p such that 5 is the largest of all prime factors of the numbers between p and the next prime (cf. A052248). |
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2
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| 7, 29, 59, 149, 179, 239, 269, 599, 809, 1619, 2999, 4049, 4799, 8999, 9719, 15359, 21599, 23039, 33749, 138239, 179999, 281249, 345599, 737279, 3455999, 6143999, 6560999, 10124999, 13668749, 15551999, 17495999, 20995199, 22118399, 23999999
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The sequence consists of 7 and the lesser of twin primes q (A001359) such that q+1 is 5-smooth (A051037) but not 3-smooth (A003586, A080193).
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EXAMPLE
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7 is a term since 8 = 2^3, 9 = 3^3, 10 = 2*5 are the numbers between 7 and the next prime 11; 149 is a term since 150 = 2*3*5^2 is the only number between 149 and the next prime 151.
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PROGRAM
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(PARI) {forprime(p=2, 24000000, q=nextprime(p+1); m=0; j=p+1; while(j<q&&m<=5, f=factor(j); a=f[matsize(f)[1], 1]; if(m<a, m=a); j++); if(m==5, print1(p, ", ")))}
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CROSSREFS
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Cf. A052248, A001359, A051037, A003586, A080193.
Adjacent sequences: A080182 A080183 A080184 this_sequence A080186 A080187 A080188
Sequence in context: A084201 A031380 A005698 this_sequence A041621 A022272 A141854
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KEYWORD
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nonn
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AUTHOR
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Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Feb 10 2003
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