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 A098515 #4 Mar 30 2012 17:38:04
%S A098515 1,2,4,27,36,675,810,12393,7552,268992,506240,6436341,2440692,
%T A098515 290698227,455503986,4897228800,520575984,519417147375,124730265582,
%U A098515 8961777270765,753891573760,203558860750848,51126160064490,4021771417157632,1305269217263592,69131417822953472,57710779788427264,1838459534098563045,63846774162325476
%N A098515 Least m such that m and m+n are both products of exactly n primes counting multiplicity.
%e A098515 4=2*2 & 6=2*3; 27=3*3*3 & 30=2*3*5; 36=2*2*3*3 & 40=2*2*2*5; 675=3*3*3*5*5 & 680=2*2*2*5*17; 810=2*3*3*3*3*5 and 816=2*2*2*2*3*17; etc.
%t A098515 f[n_Integer] := Plus @@ Transpose[FactorInteger[n]][[2]]; g[n_] := (k = 2^n; While[a = f[k]; b = f[k + n]; a != b || a != n, k++ ]; k); Do[ Print[ g[n]], {n, 12}]
%Y A098515 Cf. A097978.
%Y A098515 Cf. A097978, A135058.
%K A098515 nonn
%O A098515 1,2
%A A098515 _Robert G. Wilson v_, Sep 11 2004
%E A098515 More terms from _David Wasserman_, Feb 20 2008