A325386 Numbers n such that for any divisor d of n and some k, A048720(d,k) = n only for trivial cases d=1 and d=n, despite that n is neither prime nor in A014580.

69, 77, 81, 121, 169, 205, 209, 261, 265, 275, 289, 295, 305, 321, 323, 327, 329, 339, 377, 405, 407, 437, 453, 473, 475, 481, 493, 517, 533, 551, 553, 555, 559, 565, 575, 581, 583, 595, 625, 649, 667, 671, 699, 703, 707, 737, 747, 749, 755, 763, 767, 779, 785, 805, 815, 833, 835, 849, 851, 855, 861, 869, 871, 885, 893, 905, 923, 925

Offset

1,1

Links

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

Index entries for sequences related to polynomials in ring GF(2)[X]

Prog

(PARI)
A325560(n) = { my(p = Pol(binary(n))*Mod(1, 2)); sumdiv(n, d, my(q = Pol(binary(d))*Mod(1, 2)); !(p%q)); };
isA325386(n) = (!isprime(n) && !polisirreducible(Pol(binary(n))*Mod(1, 2)) && (2 == A325560(n)));

Crossrefs

Terms of A325559 not in A257688.

Subsequence of A005408 (odd numbers).

Cf. A014580, A325560.

Differs from A260428 for the first time at n=32, where a(32) = 555, a value missing from A260428.

Sequence in context: A256694 A166067 A253437 * A260428 A168477 A264045

Adjacent sequences: A325383 A325384 A325385 * A325387 A325388 A325389

Keyword

nonn

Author

Antti Karttunen, May 11 2019

Status

approved