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A109948
Smallest prime == 1 (mod f(n)), where f(n) = concatenation n,n-1,...,3,2,1.
3
2, 43, 643, 51853, 108643, 3925927, 45925927, 525925927, 9876543211, 65925925927, 6665925925927, 1453331851851853, 1154657766913580249, 45219875551604938273, 7873482297771358024693, 742965003571105432098767
OFFSET
1,1
MATHEMATICA
s = "1"; Do[s = ToString[n] <> s; k = ToExpression[s]; i = 1; While[ !PrimeQ[i*k + 1], i++ ]; Print[i*k + 1], {n, 2, 30}] (* Ryan Propper, Aug 01 2005 *)
CROSSREFS
Cf. A109947.
Sequence in context: A220270 A240550 A142199 * A364556 A188683 A119775
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Jul 20 2005
EXTENSIONS
More terms from Ryan Propper, Aug 01 2005
STATUS
approved