%I A121315
%S A121315 2,6,12,20,35,56,72,99,143,208,272,323,437,575,675,783,899,992,1184,
%T A121315 1517,1763,2021,2303,2597,3127,3599,3904,4288,4757,5183,5767,6399,6723,
%U A121315 7387,8633,9797,10403,11021,11663,12317,13673,15125,15875,16256,16768
%N A121315 Products of two consecutive prime powers.
%C A121315 For some algorithms for finding A034699(n), the numbers in this sequence 
               represent a worst case scenario of execution time.
%F A121315 a(n) = A000961(n)*A000961(n+1)
%e A121315 437 = 19*23 and none of the intervening integers (20,21,22) are prime 
               powers.
%t A121315 t = Join[{1}, Select[Range[2, 131], Mod[ #, # - EulerPhi[ # ]] == 0 &]]; 
               Most@t*Rest@t - Robert G. Wilson v, Sept 02 2006
%Y A121315 Cf. A000961, A034699.
%Y A121315 Sequence in context: A002378 A005991 A003274 this_sequence A078878 A095361 
               A095362
%Y A121315 Adjacent sequences: A121312 A121313 A121314 this_sequence A121316 A121317 
               A121318
%K A121315 nonn
%O A121315 1,1
%A A121315 Paul Richards (pr(AT)paulrichards.me.uk), Aug 28 2006
%E A121315 More terms from Robert G. Wilson v, Sept 02 2006