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A236769
Numbers n such that lpf(2^n -1) < lpf(2^lpf(n) -1).
3
55, 77, 161, 169, 221, 275, 299, 323, 377, 385, 391, 437, 481, 493, 539, 551, 559, 605, 611, 629, 689, 697, 703, 715, 731, 779, 793, 799, 817, 847, 893, 901, 923, 935, 949, 1001, 1007, 1027, 1045, 1073, 1079, 1121, 1127, 1147, 1159, 1241, 1265, 1271, 1273, 1309
OFFSET
1,1
COMMENTS
The numbers n for which A049479(n) < A049479(lpf(n)), where lpf(n) = A020639(n). All other n satisfy the equality (in particular all primes).
All terms are odd and composite. - Chai Wah Wu, Oct 04 2019
LINKS
PROG
(PARI) lpf(n) = vecmin(factor(n)[, 1]);
lista() = {my(vlpfmp = readvec("A049479.log")); for (i=2, #vlpfmp, if (vlpfmp[i] < vlpfmp[lpf(i)], print1(i, ", ")); ); } \\ Michel Marcus, Jan 31 2014
CROSSREFS
Cf. A049479 (a question in the third comment).
Sequence in context: A050781 A060260 A152080 * A119224 A135984 A140377
KEYWORD
nonn
AUTHOR
Thomas Ordowski, Jan 31 2014
EXTENSIONS
More terms from Michel Marcus, Jan 31 2014
More terms from Chai Wah Wu, Oct 04 2019
STATUS
approved