OFFSET
1,2
COMMENTS
From the first 3000 primes, only 200 are such that n, p[n], p[n]+n, p[n]-n and p[n]*n all are 7-less.
MATHEMATICA
id[x_]:=IntegerDigits[x]; pr[i_]:=Prime[i]; ra=Range[3000]; A104427=Select[ra, Position[Union[id[ # ], id[pr[ # ]], id[pr[ # ]+# ], id[pr[ # ]-# ], id[pr[ # ]*# ]], 7]=={}&]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 07 2005
STATUS
approved