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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 Vincenzo Librandi, Table of n, a(n) for n = 0..10000 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 Cf. A036091, A036092. Sequence in context: A323545 A017693 A013963 * A217357 A083603 A168634 Adjacent sequences: A036090 A036091 A036092 * A036094 A036095 A036096 KEYWORD nonn,easy AUTHOR N. J. A. Sloane STATUS approved

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