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 A166647 #18 Feb 06 2025 08:22:31
%S A166647 1,21,28,441,42,588,56,9261,784,882,84,12348,98,1176,1176,194481,126,
%T A166647 16464,140,18522,1568,1764,168,259308,1764,2058,21952,24696,210,24696,
%U A166647 224,4084101,2352,2646,2352,345744,266,2940,2744,388962,294,32928,308
%N A166647 Totally multiplicative sequence with a(p) = 7*(p+1) for prime p.
%H A166647 G. C. Greubel, <a href="/A166647/b166647.txt">Table of n, a(n) for n = 1..10000</a>
%F A166647 Multiplicative with a(p^e) = (7*(p+1))^e. If n = Product p(k)^e(k) then a(n) = Product (7*(p(k)+1))^e(k).
%F A166647 a(n) = A165828(n) * A003959(n) = 7^bigomega(n) * A003959(n) = 7^A001222(n) * A003959(n).
%t A166647 a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] + 1)^fi[[All, 2]])); Table[a[n]*7^(PrimeOmega[n]), {n, 1, 100}] (* _G. C. Greubel_, May 20 2016 *)
%t A166647 f[p_, e_] := (7*(p+1))^e; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* _Amiram Eldar_, Oct 18 2023 *)
%o A166647 (PARI) a(n) = {my(f = factor(n)); for (k=1, #f~, f[k,1] = 7*(f[k,1]+1)); factorback(f);} \\ _Michel Marcus_, May 21 2016
%Y A166647 Cf. A001222, A003959, A165828.
%K A166647 nonn,easy,mult
%O A166647 1,2
%A A166647 _Jaroslav Krizek_, Oct 18 2009