OFFSET
1,1
LINKS
Harry J. Smith, Table of n, a(n) for n=1..1000
MATHEMATICA
cnd[n_]:=Module[{ds=DivisorSigma[0, n]}, n*10^IntegerLength[ds]+ds]; Array[ cnd, 60] (* Harvey P. Dale, Aug 22 2019 *)
PROG
(PARI) a(n) = fromdigits(concat(digits(n), digits(numdiv(n)))); \\ Michel Marcus, Apr 02 2017
CROSSREFS
KEYWORD
nonn,base,changed
AUTHOR
Jeff Burch, Feb 28 2001
STATUS
approved