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Multiples of 4 that are primally tight and have strictly ascending powers.
2

%I #6 Apr 14 2015 11:41:02

%S 4,8,16,32,64,108,128,256,324,512,648,972,1024,1944,2048,2916,3888,

%T 4096,5832,8192,8748,11664,16384,17496,23328,26244,32768,34992,52488,

%U 65536,67500,69984,78732,104976,131072,139968,157464,209952,236196,262144

%N Multiples of 4 that are primally tight and have strictly ascending powers.

%C All numbers of the form 2^k0*p_1^k1*p_2^k2*...*p_n^k_n, where 2 <= k0 < k1 < k2 < ... < k_n and the p_i are n successive primes.

%C Subset of A073491, A133808, A133809, A133810 and A133811.

%H Reinhard Zumkeller, <a href="/A145108/b145108.txt">Table of n, a(n) for n = 1..10000</a>

%o (Haskell)

%o a145108 n = a145108_list !! (n-1)

%o a145108_list = filter ((== 0) . (`mod` 4)) a133809_list

%o -- _Reinhard Zumkeller_, Apr 14 2015

%Y Cf. A025487, A087980, A073491, A133808, A133809, A133810, A133811, A133812, A133813.

%Y Cf. A008586.

%K nonn

%O 1,1

%A _Reikku Kulon_, Oct 02 2008