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.
%I A267144 #14 Feb 16 2025 08:33:29
%S A267144 8,21,65,133,341,481,833,1045,1541,2465,2821,4033,4961,5461,6533,8321,
%T A267144 10325,11041,13333,14981,15841,18565,20501,23585,28033,30401,31621,
%U A267144 34133,35425,38081,48133,51221,56033,57685,66305,68101,73633,79381,83333,89441,95765
%N A267144 Octagonal numbers with prime indices.
%H A267144 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/OctagonalNumber.html">Octagonal Number</a>
%H A267144 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PrimeNumber.html">Prime Number</a>
%F A267144 a(n) = prime(n)*(3*prime(n) - 2) = A000040(n)*(3*A000040(n) - 2).
%F A267144 a(n) = A000567(A000040(n)).
%F A267144 a(n) = sigma_0(24^(prime(n) - 1)) = A000005(A009968(A000040(n) - 1)).
%t A267144 Table[Prime[n] (3 Prime[n] - 2), {n, 1, 45}]
%o A267144 (PARI) lista(nn) = forprime(p=2, nn, print1(p*(3*p-2), ", ")); \\ _Altug Alkan_, Jan 11 2016
%o A267144 (Magma) [NthPrime(n)*(3*NthPrime(n)-2): n in [1..50]]; // _Vincenzo Librandi_, Jan 12 2016
%o A267144 (Python)
%o A267144 from sympy import prime
%o A267144 def a(n): p = prime(n); return p*(3*p-2)
%o A267144 print([a(n) for n in range(1, 42)]) # _Michael S. Branicky_, Aug 21 2021
%Y A267144 Cf. A000040, A000567, A001248, A034953, A116995, A117961.
%K A267144 nonn,easy
%O A267144 1,1
%A A267144 _Ilya Gutkovskiy_, Jan 11 2016