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Search: id:A080187
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| A080187 |
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Primes p such that 11 is the largest of all prime factors of the numbers between p and the next prime (cf. A052248). |
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+0
2
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| 19, 97, 197, 461, 659, 1319, 1451, 2111, 2309, 2969, 3167, 3299, 4157, 5279, 7127, 9239, 10889, 11549, 15971, 16631, 22637, 25409, 26729, 29567, 30491, 34649, 34847, 55439, 55901, 64151, 87119, 92399, 98009, 110879, 118799, 152459, 164999, 176417
(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 appears to consist of 19, 97 and the lesser of twin primes q (A001359) such that q+1 is 11-smooth (A051038) but not 7-smooth (A002473, A080195).
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EXAMPLE
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97 is a term since 98 = 2*7^2, 99 = 3^2*11, 100 = 2^2*5^2 are the numbers between 97 and the next prime 101; 461 is a term since 462 = 2*3*7*11 is the only number between 461 and the next prime 463.
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PROGRAM
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(PARI) {forprime(p=2, 180000, q=nextprime(p+1); m=0; j=p+1; while(j<q&&m<=11, f=factor(j); a=f[matsize(f)[1], 1]; if(m<a, m=a); j++); if(m==11, print1(p, ", ")))}
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CROSSREFS
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Cf. A052248, A001359, A051038, A002473, A080195.
Sequence in context: A037238 A109513 A041696 this_sequence A142170 A069593 A086120
Adjacent sequences: A080184 A080185 A080186 this_sequence A080188 A080189 A080190
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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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