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 A045970 #14 Sep 19 2023 01:44:25
%S A045970 7,11,13,121,17,143,19,1331,169,187,23,1573,29,209,221,14641,31,1859,
%T A045970 37,2057,247,253,41,17303,289,319,2197,2299,43,2431,47,161051,299,341,
%U A045970 323,20449,53,407,377,22627,59,2717,61,2783,2873,451,67,190333,361,3179,403
%N A045970 a(1)=7; if n = Product p_i^e_i, n > 1, then a(n) = Product p_{i+4}^e_i.
%D A045970 From a puzzle proposed by _Marc LeBrun_.
%t A045970 f[p_, e_] := NextPrime[p, 4]^e; a[1] = 7; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* _Amiram Eldar_, Sep 19 2023 *)
%Y A045970 Cf. A045965, A045966, A045967, A045968, A045969, A045971, A045972, A045973.
%K A045970 easy,nonn
%O A045970 1,1
%A A045970 _N. J. A. Sloane_
%E A045970 More terms from _David W. Wilson_