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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A278404 Greater number in the least prime-semiprime gap of size n.

Original entry on oeis.org

3, 9, 29, 101, 346, 247, 6098, 3181, 2878, 2531, 16033, 26615, 114371, 41793, 74506, 39359, 463178, 104677, 248426, 517441, 923743, 506531, 1930846, 584237, 2560202, 4036993, 4570438, 4552391, 7879282, 4417843, 27841082, 5167619, 13683067, 9725141, 47735377, 25045807, 63305698
Offset: 1

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Author

Bobby Jacobs, Charles R Greathouse IV, Jonathan Vos Post, and Robert G. Wilson v, Nov 20 2016

Keywords

Comments

A prime-semiprime gap of n is defined as the difference between p & q, p being either a prime, A000040, or a semiprime, A001358, and q being the next greater prime or semiprime, see examples.
The corresponding numbers at the start of the prime-semiprime gaps, i.e., a(n)-n, are in A278351.

Examples

			a(1) = 3 since there is a gap of 1 between 2 and 3, both of which are primes.
a(2) = 9 since there is a gap of 2 between 7 and 9, the first is a prime and the second is a semiprime.
a(3) = 29 since there is a gap of 3 between 26, a semiprime, and 29, a prime.
a(6) = 247 because the first prime-semiprime gap of size 6 is between 241 and 247.

Links

Crossrefs

Cf. A037143, A275013, A275014, A275108, A278351.
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