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A354931 a(n) = the least k for which A345992(k) = n. 4

%I #13 Jun 16 2022 10:26:20

%S 1,6,12,20,15,42,28,24,45,110,33,156,91,70,60,112,51,342,76,140,231,

%T 198,69,168,325,234,108,476,87,930,124,96,561,170,315,1116,185,418,

%U 195,360,123,714,172,220,585,1426,141,336,245,850,204,988,159,270,385,1064,1311,522,177,3660,488,434,504,320,715,1254

%N a(n) = the least k for which A345992(k) = n.

%H Antti Karttunen, <a href="/A354931/b354931.txt">Table of n, a(n) for n = 1..3349</a> (computed using million term data file provided for A344005 by _N. J. A. Sloane_)

%F a(n) = n * A354932(n).

%t s[n_] := Module[{m = 1}, While[!Divisible[m*(m+1), n], m++]; GCD[n, m]]; a[n_] := Module[{k = n}, While[s[k] != n, k+=n]; k]; Array[a,60] (* _Amiram Eldar_, Jun 15 2022 *)

%o (PARI)

%o A345992(n) = gcd(n,A344005(n));

%o A354931(n) = for(k=1,oo,if(A345992(k)==n,return(k)));

%Y Column 1 of A354930.

%Y Cf. A344005, A345992, A354932.

%K nonn

%O 1,2

%A _Antti Karttunen_, Jun 14 2022

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Last modified May 16 12:41 EDT 2024. Contains 372552 sequences. (Running on oeis4.)