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 A145397 Numbers not of the form m*(m+1)*(m+2)/6, the non-tetrahedral numbers. 8
 2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Complement of A000292; A000040 is a subsequence. LINKS G. C. Greubel, Table of n, a(n) for n = 1..5000 Cristinel Mortici, Remarks on Complementary Sequences, Fibonacci Quart. 48 (2010), no. 4, 343-347. FORMULA A014306(a(n)) = 1; A023533(a(n)) = 0. MATHEMATICA Select[Range[100], Binomial[Floor[Surd[6*# -1, 3]] +2, 3] != # &] (* G. C. Greubel, Feb 20 2022 *) PROG (PARI) is(n)=binomial(sqrtnint(6*n, 3)+2, 3)!=n \\ Charles R Greathouse IV, Feb 22 2017 (Magma) [n: n in [1..100] | Binomial(Floor((6*n-1)^(1/3))+2, 3) ne n ]; // G. C. Greubel, Feb 20 2022 (Sage) [n for n in (1..100) if binomial( floor( real_nth_root(6*n-1, 3) ) +2, 3) != n ] # G. C. Greubel, Feb 20 2022 CROSSREFS Cf. A000040, A000292, A014306, A023533. Sequence in context: A268231 A039167 A247360 * A183570 A181092 A184526 Adjacent sequences: A145394 A145395 A145396 * A145398 A145399 A145400 KEYWORD nonn AUTHOR Reinhard Zumkeller, Oct 14 2008 EXTENSIONS Definition corrected by Ant King, Sep 20 2012 STATUS approved

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Last modified March 23 23:09 EDT 2023. Contains 361454 sequences. (Running on oeis4.)