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

1, 6, 12, 20, 15, 42, 28, 24, 45, 110, 33, 156, 91, 70, 60, 112, 51, 342, 76, 140, 231, 198, 69, 168, 325, 234, 108, 476, 87, 930, 124, 96, 561, 170, 315, 1116, 185, 418, 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

Offset: 1

Author

Antti Karttunen, Jun 14 2022

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..3349 (computed using million term data file provided for A344005 by _N. J. A. Sloane_)

Crossrefs

Column 1 of A354930.

Cf. A344005, A345992, A354932.

Programs

Mathematica

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 *)

PARI

A345992(n) = gcd(n,A344005(n));
A354931(n) = for(k=1,oo,if(A345992(k)==n,return(k)));

Formula

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