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A257658
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Primes of the form A060735(k) +- 1, where A060735 lists multiples of primorials (A002110) less than the next larger primorial.
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1
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2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 59, 61, 89, 149, 151, 179, 181, 211, 419, 421, 631, 839, 1049, 1051, 1259, 1471, 1889, 2099, 2309, 2311, 4621, 9239, 9241, 11549, 11551, 13859, 18481, 20789, 23099, 25409, 25411, 30029, 90089, 120121, 150151, 180179, 180181
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OFFSET
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1,1
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COMMENTS
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After a(9), all terms are congruent to +-1 (mod 30).
More generally, for any primorial P (cf. A002110), all terms >= P-1 are congruent to +/- 1 (mod P).- This sequence is essentially the same as A087715. - M. F. Hasler, Jul 27 2015
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LINKS
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FORMULA
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Primes among the numbers produced from A060735 +/- 1.
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EXAMPLE
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149 & 151 are in the sequence because they are primes +-1 from A060735(12) = 150. A term does not have to be a twin prime; those are found in A087732.
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MATHEMATICA
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f[n_] := Range[Prime[n + 1] - 1] Times @@ Prime@ Range@ n; Select[ Union@ Flatten@ Join[ Array[f, 6] - 1, Array[f, 7, 0] + 1], PrimeQ@# &]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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