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.

A079089 Sum of divisors of (prime(n)+1)*(prime(n+1)+1)/4.

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%I A079089 #15 Apr 07 2025 09:51:17
%S A079089 4,12,28,60,96,104,234,360,546,744,620,640,1152,1488,1815,2178,2304,
%T A079089 1728,3510,3458,3420,5952,5760,4446,4104,7056,8400,8640,5760,10160,
%U A079089 12240,11232,13824,14976,17360,11200,10080,20160,21840,21600,26208
%N A079089 Sum of divisors of (prime(n)+1)*(prime(n+1)+1)/4.
%H A079089 Reinhard Zumkeller, <a href="/A079089/b079089.txt">Table of n, a(n) for n = 1..10000</a>
%F A079089 a(n) = A000203(A079079(n)).
%t A079089 a[n_] := DivisorSigma[1, (Prime[n]+1) * (Prime[n+1]+1) / 4]; Array[a, 100] (* _Amiram Eldar_, Apr 06 2025 *)
%o A079089 (Haskell)
%o A079089 a079089 = a000203 . a079079  -- _Reinhard Zumkeller_, Oct 08 2012
%o A079089 (PARI) a(n) = sigma((prime(n)+1)*(prime(n+1)+1)/4); \\ _Amiram Eldar_, Apr 06 2025
%Y A079089 Cf. A000203, A079079, A079088, A079090, A079091.
%K A079089 nonn
%O A079089 1,1
%A A079089 _Reinhard Zumkeller_, Dec 22 2002