

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.


2



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
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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



