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A048853
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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).
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24
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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, 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, 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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| a(A192545(n)) = 0. [Reinhard Zumkeller, Jul 05 2011]
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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EXAMPLE
| Altering the number 13 gives eight primes: 11, 17, 19, 23, 43, 53, 73, 83, so a(13)=8.
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MAPLE
| 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
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MATHEMATICA
| a[n_] := Module[{idn = IntegerDigits[n], id, np = 0}, Do[id = idn; If[ id[[j]] != k, id[[j]] = k; If[ id[[1]] != 0 && PrimeQ[ FromDigits[id]], np = np + 1]], {j, 1, Length[idn]}, {k, 0, 9}]; np]; Table[a[n], {n, 1, 105}] (* From Jean-François Alcover, Dec 01 2011 *)
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PROG
| (Haskell)
import Data.List (inits, tails, nub)
a048853 n = (sum $ map (a010051 . read) $ tail $ nub $ concat $ zipWith
(\its tls -> map ((\xs ys d -> xs ++ (d:ys)) its tls) "0123456789")
(map init $ tail $ inits $ show n) (tail $ tails $ show n)) - a010051 n
-- Reinhard Zumkeller, Jul 05 2011
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CROSSREFS
| Cf. A050652-A050673.
Cf. A010051.
Sequence in context: A026858 A188885 A129344 * A179845 A180217 A011762
Adjacent sequences: A048850 A048851 A048852 * A048854 A048855 A048856
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KEYWORD
| base,nonn,easy,nice
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AUTHOR
| G. L. Honaker, Jr. (honak3r(AT)gmail.com) and Patrick De Geest (pdg(AT)worldofnumbers.com).
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