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 A073325 a(n) = least k > 0 such that prime(k) == n (mod k). 2
 1, 2, 3, 4, 75, 9, 79, 18, 17, 10, 19, 20, 91, 22, 23, 41, 83, 24, 16049, 43, 2711, 94, 25, 26, 95, 198, 449, 452, 99, 50, 451, 48, 453, 1072, 447, 54, 16043, 55, 2719, 56, 459, 57, 101, 472, 100371, 62, 105, 102, 103, 104, 467, 110, 107, 65, 109, 63, 115, 118, 117 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS First appearance of n-1 in A004648. Are all positive integers present in A004648 and hence in this sequence? - Zak Seidov, Sep 02 2012 LINKS Zak Seidov, Table of n, a(n) for n = 1..301 FORMULA a(n) = Min{x; Mod[A000040(x), x]=n} = Min{x; A004648[x]=n}. EXAMPLE a(4) = 75 as prime(75) = 379 == 4 (mod 75). a(44) = 100371 since prime(100371) = 1304867 == 44 (mod 100371) and prime(k) <> 44 (mod k) for k < 100371. MATHEMATICA nn = 60; f[x_] := Mod[Prime[x], x]; t = Table[0, {nn}]; k = 0; While[Times @@ t == 0, k++; n = f[k]; If[n <= nn && t[[n]] == 0, t[[n]] = k]]; Join[{1}, t] lk[n_]:=Module[{k=1}, While[Mod[Prime[k], k]!=n, k++]; k]; Array[lk, 60, 0] (* Harvey P. Dale, Nov 29 2013 *) PROG (PARI) stop=110000; for(n=0, 59, k=1; while(k

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Last modified October 16 09:02 EDT 2021. Contains 348041 sequences. (Running on oeis4.)