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A036093 Centered cube numbers: (n+1)^15 + n^15. 2
1, 32769, 14381675, 1088090731, 31591319949, 500702562701, 5217746494519, 39931933598775, 241075504183481, 1205891132094649, 5177248169415651, 19584269744002019, 66592914588677125, 206753988571902981 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Never prime nor semiprime, nor triprime, as a(n) = (2n+1) * (n^2 + n + 1) * (n^4 + 2n^3 + 4n^2 + 3n + 1) * (n^8 + 4n^7 + 30n^6 + 76n^5 + 99n^4 + 76n^3 + 35n^2 + 9n + 1). Has the nontrivial minimum 4 prime factors when n is in {1, 5, 105, ...}. - Jonathan Vos Post, Aug 27 2011
REFERENCES
B. K. Teo and N. J. A. Sloane, Magic numbers in polygonal and polyhedral clusters, Inorgan. Chem. 24 (1985), 4545-4558.
LINKS
EXAMPLE
1^15 + (1+1)^15 = 32769 = 3^2 * 11 * 331 which has the nontrivial minimum 4 prime factors (see A014613).
MATHEMATICA
Total/@Partition[Range[0, 20]^15, 2, 1] (* Harvey P. Dale, Apr 18 2013 *)
PROG
(Magma) [(n+1)^15+n^15: n in [0..20]]; // Vincenzo Librandi, Aug 28 2011
(PARI) a(n)=(n+1)^15+n^15 \\ Charles R Greathouse IV, Aug 30 2017
CROSSREFS
Sequence in context: A323545 A017693 A013963 * A217357 A083603 A168634
KEYWORD
nonn,easy
AUTHOR
STATUS
approved

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Last modified June 23 11:52 EDT 2024. Contains 373648 sequences. (Running on oeis4.)