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A317049 Numbers k such that both k and k + 3 are consecutive deficient numbers. 4
5774, 5983, 7423, 11023, 21734, 21943, 26143, 27403, 39374, 43063, 49663, 56923, 58694, 61423, 69614, 70783, 76543, 77174, 79694, 81079, 81674, 82003, 84523, 84643, 89774, 91663, 98174, 103454, 104894, 106783, 109394, 111823, 116654, 116863, 120014, 121903 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

MAPLE

with(numtheory):  A:=select(k->sigma(k)<2*k, [$1..130000]):

a:=seq(A[i], i in select(k->A[k+1]-A[k]=3, [$1..nops(A)-1]));

MATHEMATICA

SequencePosition[Table[If[DivisorSigma[1, n]<2n, 1, 0], {n, 122000}], {1, 0, 0, 1}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 28 2019 *)

PROG

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

a:=List(Filtered([1..Length(A)-1], i->A[i+1]-A[i]=3), j->A[j]);

CROSSREFS

Subsequence of A005100.

Numbers j such that both k and k + j are consecutive deficient numbers: A317047 (j=1), A317048 (j=2), this sequence (j=3).

Sequence in context: A053862 A235393 A246421 * A329525 A331202 A096399

Adjacent sequences:  A317046 A317047 A317048 * A317050 A317051 A317052

KEYWORD

nonn

AUTHOR

Muniru A Asiru, Aug 04 2018

STATUS

approved

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Last modified June 5 01:27 EDT 2020. Contains 334828 sequences. (Running on oeis4.)