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A173014 a(1) = 1, for n >= 2; a(n) = the smallest number h such that sigma(h) = A000203(h) = a(n-1) + 4, a(n) = 0 if no such number exists.

%I A173014 #7 Nov 21 2013 12:49:59
%S A173014 1,0,3,4,7,0,3,4,7,0,3,4,7,0,3,4,7,0,3,4,7,0,3,4,7,0,3,4,7,0,3,4,7,0,
%T A173014 3,4,7,0,3,4,7,0,3,4,7,0,3,4,7,0,3,4,7,0,3,4,7,0,3,4,7,0,3,4,7,0,3,4,
%U A173014 7,0,3,4,7
%N A173014 a(1) = 1, for n >= 2; a(n) = the smallest number h such that sigma(h) = A000203(h) = a(n-1) + 4, a(n) = 0 if no such number exists.
%C A173014 a(1) = 1, a(n) = periodic sequence with period (0, 3, 4, 7) for n >= 2.
%F A173014 A000203(a(n)) = a(n-1) + 4 for n >= 2.
%t A173014 PadRight[{1},80,{7,0,3,4}] (* _Harvey P. Dale_, May 09 2012 *)
%o A173014 (PARI) a(n)=if(n>1,[4, 7, 0, 3][n%4+1],1) \\ _Charles R Greathouse IV_, Feb 19 2013
%Y A173014 Cf. A000035, A173012, A173013, A173015, A173016.
%K A173014 nonn,easy
%O A173014 1,3
%A A173014 _Jaroslav Krizek_, Nov 06 2010