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A055006 a(n) is the least multiple of n such that a(n) = 1 mod k for all integers k with 1 < k < n and k relatively prime to n. 0

%I #15 Sep 13 2023 12:26:55

%S 1,2,3,4,25,6,301,736,2241,190,25201,4236,83161,19306,64065,135136,

%T 7207201,85086,49008961,49468420,36951201,27776386,698377681,

%U 855189336,25700298625,2445441076,74364290001,13624600276,2248776129601,6254036790,39594522567601

%N a(n) is the least multiple of n such that a(n) = 1 mod k for all integers k with 1 < k < n and k relatively prime to n.

%t Table[Block[{m = 1, t = Select[Range[2, n - 1], CoprimeQ[#, n] &]}, While[! AllTrue[t, Mod[m n, #] == 1 &], m++]; m n], {n, 20}] (* _Michael De Vlieger_, Mar 08 2022 *)

%o (PARI) isok(m, n) = for (k=2, n-1, if ((gcd(k, n)==1) && ((m % k) !=1), return(0))); return(1);

%o a(n) = my(m=n); while (!isok(m,n), m+=n); m; \\ _Michel Marcus_, Mar 08 2022

%K nonn

%O 1,2

%A _Stephen G Penrice_, May 30 2000

%E More terms from _Sean A. Irvine_, Mar 07 2022

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Last modified March 28 17:42 EDT 2024. Contains 371254 sequences. (Running on oeis4.)