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A036101
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Centered cube numbers: (n+1)^23+n^23.
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2
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1, 8388609, 94151567435, 70462887356491, 11991297699255789, 801651152008680941, 28158477563134519159, 617664557698786568055, 9453233930011206747641, 108862938119652501095929
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Can never be prime, as a(n) = (2n + 1) * (n^22 + 11n^21 + 121n^20 + 825n^19 + 4015n^18 + 14817n^17 + 43065n^16 + 101046n^15 + 194634n^14 + 311278n^13 + 416394n^12 + 467842n^11 + 442118n^10 + 350974n^9 + 233108n^8 + 128603n^7 + 58277n^6 + 21335n^5 + 6157n^4 + 1349n^3 + 211n^2 + 21n + 1). a(1) is semiprime (A001358) [Jonathan Vos Post, Aug 28 2011]
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REFERENCES
| B. K. Teo and N. J. A. Sloane, Magic numbers in polygonal and polyhedral clusters, Inorgan. Chem. 24 (1985), 4545-4558.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..10000
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EXAMPLE
| a(2) = 1^23 + (1+1)^23 = 8388609 = 3 * 2796203, which is semiprime.
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PROG
| (MAGMA) [(n+1)^23+n^23: n in [0..20]]; // Vincenzo Librandi, Aug 28 2011
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CROSSREFS
| Cf. A010811, A036099, A036100.
Sequence in context: A010811 A017709 A013971 * A160673 A049362 A205179
Adjacent sequences: A036098 A036099 A036100 * A036102 A036103 A036104
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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