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Numbers n such that n, p[n], p[n]+n, p[n]-n and p[n]*n all are 3-less.
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%I #3 Mar 30 2012 17:26:11

%S 5,7,8,20,25,26,45,47,50,95,100,101,102,105,107,109,110,121,145,149,

%T 155,156,158,160,161,165,167,168,169,171,177,180,181,205,209,210,271,

%U 272,275,277,279,284,288,290,292,297,299,628,629,745,751,761,764,765,769

%N Numbers n such that n, p[n], p[n]+n, p[n]-n and p[n]*n all are 3-less.

%C 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 3-less.

%t id[x_]:=IntegerDigits[x];pr[i_]:=Prime[i];ra=Range[3000];A104423=Select[ra, Position[Union[id[ # ], id[pr[ # ]], id[pr[ # ]+# ], id[pr[ # ]-# ], id[pr[ # ]*# ]], 3]=={}&]

%Y Cf. A104419-A104428.

%K nonn,base

%O 1,1

%A _Zak Seidov_, Mar 07 2005