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 A097978 #17 Mar 01 2017 12:47:44 %S A097978 1,2,33,102,1326,115005,31295895,159282123,9617162170,1535531452026, %T A097978 1960347077019695,16513791577659519,271518698440871310 %N A097978 a(n) = least m such that m and m+n are both products of exactly n distinct primes. %C A097978 Note that a(n) and a(n)+n are required to be squarefree (compare A135058). - _David Wasserman_, Feb 19 2008 %C A097978 If we change "exactly n" to "at least n", the sequence is still the same at least through a(12). - _David Wasserman_, Feb 19 2008 %C A097978 a(13) <= 592357638037885411965. - _David Wasserman_, Feb 19 2008 %F A097978 a(n) = min{m: A001221(m) = A001222(m) = A001221(m+n) = A001222(m+n)= n}. - _R. J. Mathar_, Mar 01 2017 %e A097978 a(2) = 33 because 33 and 35 are both in A006881. %e A097978 a(3) = 102 because 102 and 105 are both in A007304. %e A097978 a(4) = 1326 because 1326 and 1330 are both in A046386. %t A097978 f[n_] := Block[{lst = FactorInteger[n], a, b}, a = Plus @@ Last /@ lst; b = Length[lst]; If[a == b, b, 0]]; g[n_] := Block[{k = Product[ Prime[i], {i, n}]}, While[ f[k] != n || f[k] != f[k + n], k++ ]; k]; Do[ Print[ g[n]], {n, 1, 6}] (* _Robert G. Wilson v_, Sep 11 2004 *) %Y A097978 Cf. A098515. A135058 (without regard to multiplicity). %K A097978 more,nonn %O A097978 0,2 %A A097978 _Lekraj Beedassy_, Sep 07 2004 %E A097978 Edited and extended by Mark Hudson (mrmarkhudson(AT)hotmail.com), Sep 08 2004 %E A097978 More terms from _David Wasserman_, Feb 19 2008