OFFSET
1,1
MAPLE
with(numtheory): A:=select(n->sigma(n)>2*n, [$1..20000]): a:=select(j->A[j+1]=A[j]+3, [$1..nops(A)-1]);
MATHEMATICA
Position[Map[{#1, #2 - 3} & @@ # &, Partition[Select[Range[12000], DivisorSigma[1, #] > 2 # &], 2, 1]], _?(SameQ @@ # &)][[All, 1]] (* Michael De Vlieger, Jun 29 2018 *)
PROG
(GAP) A:=Filtered([1..20000], n->Sigma(n)>2*n);; a:=Filtered([1..Length(A)-1], i->A[i+1]=A[i]+3);
(PARI) lista(nn) = {my(va = select(x->(sigma(x) > 2*x), [1..nn]), dva = vector(#va-1, k, va[k+1] - va[k])); select(x->(x==3), dva, 1); } \\ Michel Marcus, Jul 03 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Muniru A Asiru, Jun 25 2018
STATUS
approved