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%I A042970 #22 Sep 08 2022 08:44:55
%S A042970 0,0,0,2,0,2,0,6,0,2,0,0,0,2,0,6,0,2,0,16,0,2,0,4,0,2,0,20,0,0,0,6,0,
%T A042970 2,0,24,0,2,0,20,0,6,0,28,0,2,0,12,0,2,0,32,0,20,0,0,0,2,0,4,0,2,0,6,
%U A042970 0,42,0,40,0,42,0,52,0,2,0,44,0,20,0,20,0,2,0,0,0,2,0,48,0,0,0,52,0,2,0
%N A042970 a(n) = binomial(n, floor(n/2)) mod n.
%C A042970 Value 924 occurs for 248 times among the first 20000 terms (see the horizontal stripe near y=1000 in the scatter plot). Where does it originate from? - _Antti Karttunen_, Feb 13 2019
%H A042970 Antti Karttunen, <a href="/A042970/b042970.txt">Table of n, a(n) for n = 1..20000</a>
%e A042970 a(10) = binomial(10,5) mod 10 = 252 mod 10 = 2.
%p A042970 a:=n->modp(binomial(n,floor(n/2)),n): seq(a(n),n=1..110); # _Muniru A Asiru_, Feb 17 2019
%t A042970 Table[Mod[Binomial[n, Floor[n/2]], n], {n,1,110}] (* _G. C. Greubel_, Feb 17 2019 *)
%o A042970 (PARI) a(n) = binomial(n, n\2) % n; \\ _Michel Marcus_, May 14 2018
%o A042970 (Magma) [Binomial(n, Floor(n/2)) mod n: n in [1..110]]; // _G. C. Greubel_, Feb 17 2019
%o A042970 (Sage) [mod(binomial(n,floor(n/2)), n) for n in (1..110)] # _G. C. Greubel_, Feb 17 2019
%Y A042970 Cf. A001405, A020475.
%K A042970 nonn,look
%O A042970 1,4
%A A042970 _Labos Elemer_
%E A042970 Name corrected by _Jon E. Schoenfield_, May 13 2018

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