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16, 232, 59281, 10059281, 4049575228945, 1950244643588320, 30041944445326335483061, 32095019157463691981298869, 142108579247039194637916834814494, 108199957883829576141601541930838816381470, 118558455387984539329682688832638841343258239487
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OFFSET
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1,1
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COMMENTS
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a(n) is prime for n = 3, 4, ..., a(n) is semiprime for n = 7, 8, 11, ...
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LINKS
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FORMULA
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EXAMPLE
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a(1) = 16 because semiprime(1)^prime(1) = 4^2 = 16.
a(2) = 232 because 4^2 + 6^3 = 232.
a(3) = 59281 = 4^2 + 6^3 + 9^5, which is a prime.
a(4) = 10059281 = 4^2 + 6^3 + 9^5 + 10^7, which is a prime.
a(7) = 4^2 + 6^3 + 9^5 + 10^7 + 14^11 + 15^13 + 21^17 = 428081461 * 70178102025601, which is semiprime.
a(8) = 4^2 + 6^3 + 9^5 + 10^7 + 14^11 + 15^13 + 21^17 + 22^19 = 47 * 682872748031142382580827, which is semiprime.
a(11) = 4^2 + 6^3 + 9^5 + 10^7 + 14^11 + 15^13 + 21^17 + 22^19 + 25^23 + 26^29 + 33^31 = 17 * 6974026787528502313510746401919931843721072911 which is semiprime.
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CROSSREFS
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KEYWORD
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easy,nonn,less
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AUTHOR
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STATUS
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approved
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