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A114314
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Difference between first odd semiprime > 7^n and 7^n.
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0
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8, 2, 0, 12, 6, 10, 2, 6, 12, 2, 4, 12, 2, 10, 2, 4, 10, 6, 4, 4, 12, 24, 10, 10, 10, 4, 2, 30, 10, 4, 4, 30, 12, 2, 10, 4, 10, 10, 54, 10, 12, 22, 10, 24, 2, 4, 88, 16, 16, 22, 30
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| A098147 is difference between first odd semiprime > 10^n and 10^n.
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FORMULA
| a(n) = minimum integer k such that 7^n + k is an element of A046315. a(n) = minimum integer k such that A000420(n) + k is an element of A046315.
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EXAMPLE
| a(0) = 8 because 7^0 + 8 = 9 = 3^2 is an odd semiprime.
a(1) = 2 because 7^1 + 2 = 9 = 3^2 is an odd semiprime.
a(2) = 0 because 7^2 + 0 = 49 = 7^2 is an odd semiprime; there are no more zero values.
a(3) = 12 because 7^3 + 12 = 355 = 5 * 71.
a(4) = 6 because 7^4 + 6 = 2407 = 29 * 83 (brilliant).
a(5) = 10 because 7^5 + 10 = 16817 = 67 * 251.
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CROSSREFS
| Cf. A000351, A001358, A098147.
Sequence in context: A011105 A098829 A190404 * A080729 A164800 A011008
Adjacent sequences: A114311 A114312 A114313 * A114315 A114316 A114317
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KEYWORD
| easy,nonn
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AUTHOR
| Jonathan Vos Post (jvospost3(AT)gmail.com), Feb 05 2006
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