A350083 - OEIS

A350083

a(n) = (A006935(n) - 1) / ord(2,A006935(n)/2), where ord(k,m) is the multiplicative order of k modulo m.

1, 617, 1305, 9339, 225, 5297, 6985, 1549, 174233, 46549, 93701, 66879, 431087, 593887, 1288921, 446275, 43685, 1205, 3361, 2577225, 1313, 430739, 177301, 8541, 13067, 474525, 561301, 84725, 158873, 725725, 3851, 14019, 128861, 1090301, 2529, 430667, 541673

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OFFSET

1,2

COMMENTS

List of (2*k-1) / ord(2,k) where k ranges over the odd numbers such that 2^(2*k-1) == 1 (mod k).

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..1319

FORMULA

a(n) = (2*A347906(n) - 1) / ord(2,A347906(n)) = (A006935(n) - 1) / A350084(n).

EXAMPLE

A006935(2) = 161038, so a(2) = (161038 - 1) / ord(2,161038/2) = 617.

A006935(3) = 215326, so a(3) = (215326 - 1) / ord(2,215326/2) = 1305.

PROG

(PARI) list(lim) = my(v=[], d); forstep(k=1, lim, 2, if((2*k-1)%(d=znorder(Mod(2, k)))==0, v=concat(v, (2*k-1)/d))); v \\ gives a(n) for A347906(n) <= lim

CROSSREFS

Cf. A006935, A347906, A350084, A300101, A174590.

Sequence in context: A221040 A221503 A275048 * A275739 A108818 A288412

Adjacent sequences: A350080 A350081 A350082 * A350084 A350085 A350086

KEYWORD

nonn

AUTHOR

Jianing Song, Dec 12 2021

STATUS

approved