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

4340, 4494, 5572, 8278, 16351, 16506, 19666, 20614, 29619, 32386, 37349, 42805, 44134, 46183, 52345, 53222, 57553, 58033, 59930, 60966, 61412, 61657, 63553, 63643, 67509, 68925, 73829, 77801, 78888, 80309, 82269, 84099, 87737, 87892, 90270, 91697, 91966

Offset

1,1

Links

Muniru A Asiru, Table of n, a(n) for n = 1..10000

Formula

Sequence is { k | A005100(k+1) = A005101(k) + 3 }.

Sequence is { k | A125238(k) = 3 }.

Maple

with(numtheory): A:=select(k->sigma(n)<2*k, [$1..130000]):
a:=select(j->A[j+1]=A[j]+3, [$1..nops(A)-1]);

Mathematica

Position[Differences[Select[Range[125000], DivisorSigma[1, #] < 2*# &]], 3] // Flatten (* Amiram Eldar, Mar 15 2024 *)

Prog

(GAP) A:=Filtered([1..130000], k->Sigma(k)<2*k);;  a:=Filtered([1..Length(A)-1], i->A[i+1]=A[i]+3);

Crossrefs

A317049 is the main sequence for this entry.

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).

Cf. A005100, A125238.

Sequence in context: A298431 A172884 A172915 * A259961 A252431 A251947

Adjacent sequences: A317043 A317044 A317045 * A317047 A317048 A317049

Keyword

nonn

Author

Muniru A Asiru, Aug 04 2018

Status

approved