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%I #13 Aug 22 2018 06:26:40
%S 1,2,3,4,7,8,9,10,13,14,15,16,21,22,25,26,31,32,33,34,37,38,43,44,45,
%T 46,49,50,51,52,57,58,61,62,63,64,67,68,73,74,75,76,81,82,85,86,91,92,
%U 93,94,97,98,105,106,109,110,115,116,117,118,121,122,123
%N Numbers k such that both k and k + 1 are deficient.
%H Muniru A Asiru, <a href="/A317047/b317047.txt">Table of n, a(n) for n = 1..10000</a>
%p A:=select(k->sigma(k)<2*k,[$1..200]): a:=seq(A[i],i in select(n->A[n+1]-A[n]=1,[$1..nops(A)-1]));
%o (GAP) A:=Filtered([1..200],k->Sigma(k)<2*k);;
%o a:=List(Filtered([1..Length(A)-1],i->A[i+1]-A[i]=1),j->A[j]);
%o (PARI) isok(n) = (sigma(n) < 2*n) && (sigma(n+1) < 2*(n+1)); \\ _Michel Marcus_, Aug 20 2018
%Y Subsequence of A005100.
%Y Numbers j such that both k and k + j are consecutive deficient numbers: this sequence (j=1), A317048 (j=2), A317049 (j=3).
%K nonn
%O 1,2
%A _Muniru A Asiru_, Aug 04 2018
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