Search: id:A048853
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%I A048853
%S A048853 4,3,3,4,3,4,3,4,4,4,7,4,8,4,4,4,7,4,7,2,7,2,6,2,2,2,7,2,5,2,5,2,8,2,2,
%T A048853 2,5,2,7,3,6,3,7,3,3,3,6,3,8,2,7,2,6,2,2,2,7,2,5,2,5,2,8,2,2,2,5,2,7,3,
%U A048853 6,3,7,3,3,3,8,3,6,2,7,2,6,2,2,2,7,2,5,1,6,1,7,1,1,1,4,1,6,4,10,4,8,4,
               4
%N A048853 Number of primes (different from n) that can be produced by altering 
               one digit of decimal expansion of n (without changing the number 
               of digits).
%e A048853 Altering the number 13 gives eight primes: 11, 17, 19, 23, 43, 53, 73, 
               83, so a(13)=8.
%p A048853 A048853 := proc(n::integer) local resul,ddigs,d,c,tmp ; resul := 0 ; 
               ddigs := convert(n,base,10) ; for d from 1 to nops(ddigs) do for 
               c from 0 to 9 do if c = 0 and d = nops(ddigs) then continue ; else 
               if c <> op(d,ddigs) then tmp := [op(1..d-1,ddigs),c,op(d+1..nops(ddigs),
               ddigs)] ; tst := sum(op(i,tmp)*10^(i-1),i=1..nops(tmp)) ; if isprime(tst) 
               then resul := resul+1 ; fi ; fi ; fi ; od : od ; RETURN(resul) ; 
               end: for n from 1 to 90 do printf("%d,",A048853(n)) ; od ; - R. J. 
               Mathar (mathar(AT)strw.leidenuniv.nl), Apr 25 2006
%Y A048853 Cf. A050652-A050673.
%Y A048853 Sequence in context: A059124 A026858 A129344 this_sequence A011762 A063571 
               A005589
%Y A048853 Adjacent sequences: A048850 A048851 A048852 this_sequence A048854 A048855 
               A048856
%K A048853 base,nonn,easy,nice
%O A048853 1,1
%A A048853 G. L. Honaker, Jr. (honak3r(AT)gmail.com) and Patrick De Geest (pdg(AT)worldofnumbers.com).

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