OFFSET
1,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Range[700], DivisorSigma[0, #]==IntegerDigits[#][[1]]&] (* Harvey P. Dale, Aug 04 2021 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
EXTENSIONS
1 prepended. - R. J. Mathar, Jul 26 2015
STATUS
approved