A354998 Smallest divisor d of n for which A344005(d) = A344005(n), where A344005(n) is the smallest positive integer m such that n divides m*(m+1).

1, 1, 3, 4, 5, 3, 7, 8, 9, 5, 11, 4, 13, 7, 15, 16, 17, 9, 19, 5, 7, 11, 23, 24, 25, 13, 27, 28, 29, 15, 31, 32, 33, 17, 35, 9, 37, 19, 13, 40, 41, 7, 43, 44, 45, 23, 47, 16, 49, 25, 51, 13, 53, 27, 11, 8, 19, 29, 59, 60, 61, 31, 63, 64, 65, 33, 67, 17, 69, 35, 71, 9, 73, 37, 25, 76, 77, 13, 79, 16, 81, 41, 83, 84

Offset

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

Formula

a(n) = n / A354999(n).

Mathematica

s[n_] := Module[{m = 1}, While[! Divisible[m*(m + 1), n], m++]; m]; a[n_] := Module[{sn = s[n], ds = Divisors[n]}, Do[If[s[d] == sn, Return[d]], {d, ds}]]; Array[a, 100] (* Amiram Eldar, Jun 17 2022 *)

Prog

(PARI)
A344005(n) = for(m=1, oo, if((m*(m+1))%n==0, return(m))); \\ From A344005
A354998(n) = { my(x=A344005(n)); fordiv(n, d, if(A344005(d)==x, return(d))); };

Crossrefs

Cf. A344005, A354991, A354992, A354999.

Cf. also A344758, A346088.

Sequence in context: A176774 A373921 A126352 * A094758 A283971 A348173

Adjacent sequences: A354995 A354996 A354997 * A354999 A355000 A355001

Keyword

nonn

Author

Antti Karttunen, Jun 17 2022

Status

approved