OFFSET
1,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
MATHEMATICA
f[n_] := DivisorSigma[0, n]; lst = {}; n = 2; While[Length[lst] < 40, n++; If[f[n-2] == f[n] == f[n+2] == 12, AppendTo[lst, n]]]; lst (* T. D. Noe, May 26 2011 *)
Select[Range[2, 5000], DivisorSigma[0, # - 2] == 12 && DivisorSigma[0, #] == 12 && DivisorSigma[0, # + 2] == 12 &] (* G. C. Greubel, Dec 29 2017 *)
PROG
(PARI) isok(n) = (n>2) && (numdiv(n-2)==12) && (numdiv(n)==12) && (numdiv(n+2)==12); \\ Michel Marcus, Dec 30 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, May 15 2011
EXTENSIONS
Corrected and extended by T. D. Noe, May 26 2011
STATUS
approved