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 A045968 #23 Sep 19 2023 01:45:22
%S A045968 5,7,11,49,13,77,17,343,121,91,19,539,23,119,143,2401,29,847,31,637,
%T A045968 187,133,37,3773,169,161,1331,833,41,1001,43,16807,209,203,221,5929,
%U A045968 47,217,253,4459,53,1309,59,931,1573,259,61,26411,289,1183,319,1127,67,9317,247
%N A045968 a(1)=5; for n >= 2, if n = Product p_i^e_i, then a(n) = Product p_{i+3}^e_i.
%D A045968 From a puzzle proposed by _Marc LeBrun_.
%e A045968 If n = 9 = 3^2, then a(n) = 11^2 = 121 (since 11 is the third prime after 3).
%t A045968 f[p_, e_] := NextPrime[p, 3]^e; a[1] = 5; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* _Amiram Eldar_, Sep 19 2023 *)
%Y A045968 Cf. A045965, A045966, A045967, A045969, A045970, A045971, A045972, A045973.
%K A045968 easy,nonn
%O A045968 1,1
%A A045968 _N. J. A. Sloane_
%E A045968 More terms from _David W. Wilson_
%E A045968 Erroneous linear recurrence deleted by _Harvey P. Dale_, May 07 2018