cp's OEIS Frontend

A317046 Numbers k such that A(k+1) = A(k) + 3, where A() = A005100() are the deficient numbers.

%I A317046 #18 Mar 15 2024 05:37:44
%S A317046 4340,4494,5572,8278,16351,16506,19666,20614,29619,32386,37349,42805,
%T A317046 44134,46183,52345,53222,57553,58033,59930,60966,61412,61657,63553,
%U A317046 63643,67509,68925,73829,77801,78888,80309,82269,84099,87737,87892,90270,91697,91966
%N A317046 Numbers k such that A(k+1) = A(k) + 3, where A() = A005100() are the deficient numbers.
%H A317046 Muniru A Asiru, <a href="/A317046/b317046.txt">Table of n, a(n) for n = 1..10000</a>
%F A317046 Sequence is { k | A005100(k+1) = A005101(k) + 3 }.
%F A317046 Sequence is { k | A125238(k) = 3 }.
%p A317046 with(numtheory): A:=select(k->sigma(n)<2*k,[$1..130000]):
%p A317046 a:=select(j->A[j+1]=A[j]+3,[$1..nops(A)-1]);
%t A317046 Position[Differences[Select[Range[125000], DivisorSigma[1, #] < 2*# &]], 3] // Flatten (* _Amiram Eldar_, Mar 15 2024 *)
%o A317046 (GAP) A:=Filtered([1..130000],k->Sigma(k)<2*k);;  a:=Filtered([1..Length(A)-1],i->A[i+1]=A[i]+3);
%Y A317046 A317049 is the main sequence for this entry.
%Y A317046 Numbers k such that A(k+1) = A(k) + j, where A() = A005100() are the deficient numbers: A317044 (j=1), A317045 (j=2), this sequence (j=3).
%Y A317046 Cf. A005100, A125238.
%K A317046 nonn
%O A317046 1,1
%A A317046 _Muniru A Asiru_, Aug 04 2018