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A050673
a(n) is the smallest prime such that the number of primes produced according to rules stipulated in Honaker's A048853 is n.
13
6983, 4409, 2, 97, 29, 23, 11, 13, 131, 101, 107, 1459, 1297, 1423, 15731, 13597, 105967, 249533, 1006391, 2391041, 10866913, 77538289, 107640251, 120988597, 119628479, 10168288073, 1812918883, 115829122963
OFFSET
1,1
COMMENTS
a(26) > 10^10. a(27) = 1812918883. a(n) > 10^10 for n >= 28. - Donovan Johnson, May 08 2010
a(29) > 1.9*10^11. - Giovanni Resta, Aug 14 2013
FORMULA
A048853(a(n))=n. a(n) is prime. a(n)>=A050662(n). - R. J. Mathar, Apr 25 2006
MAPLE
A048853 := proc(n::integer) local resul, ddigs, d, c, tmp, tst ; 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: A050673 := proc(n::integer) local i, p; for p from 1 to 10000000 do i := ithprime(p) ; if A048853(i) = n then RETURN(i) ; fi ; od ; RETURN(-1) ; end : for n from 1 to 90 do print(A050673(n)) ; od ; # R. J. Mathar, Apr 25 2006
CROSSREFS
Cf. A048853, first terms of A050663-A050672, A050662.
Sequence in context: A305718 A237237 A251651 * A050663 A114615 A209879
KEYWORD
nonn,base,more
AUTHOR
Patrick De Geest, Jul 15 1999
EXTENSIONS
a(22)-a(25) from Donovan Johnson, May 08 2010
a(26) and a(28) from Giovanni Resta, Aug 14 2013
STATUS
approved