cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A179893 a(n) = 3/2 * (prime(n)-1).

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%I A179893 #30 Jan 30 2025 16:28:44
%S A179893 3,6,9,15,18,24,27,33,42,45,54,60,63,69,78,87,90,99,105,108,117,123,
%T A179893 132,144,150,153,159,162,168,189,195,204,207,222,225,234,243,249,258,
%U A179893 267,270,285,288,294,297,315,333,339,342,348,357,360,375,384,393,402,405
%N A179893 a(n) = 3/2 * (prime(n)-1).
%H A179893 G. C. Greubel, <a href="/A179893/b179893.txt">Table of n, a(n) for n = 2..1000</a>
%F A179893 A179545 / prime(n).
%F A179893 a(n) = 3*A005097(n-1). - _R. J. Mathar_, Aug 15 2010
%e A179893 For n=4, the fourth prime is 7, so a(4) = (3/2) * (7 - 1) = 9. Note that since the sequence starts at n=2, prime(n) is odd, so a(n) is an integer. - _Michael B. Porter_, Jul 19 2016
%t A179893 Table[(3/2)*(Prime[n] - 1), {n,2,100}] (* _G. C. Greubel_, Jun 17 2016 *)
%o A179893 (PARI) a(n)=prime(n)\2*3 \\ _Charles R Greathouse IV_, May 19 2011
%o A179893 (Magma) [3/2*(NthPrime(n)-1): n in [2..60]]; // _Vincenzo Librandi_, Jun 18 2016
%Y A179893 Cf. A000040, A179545.
%K A179893 easy,nonn
%O A179893 2,1
%A A179893 _Odimar Fabeny_, Jul 30 2010, Aug 02 2010
%E A179893 More terms from _R. J. Mathar_, Aug 15 2010