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A188631 Numbers k such that d(k-1) < d(k) < d(k+1) where d(k) is the number of divisors of k. 2
62, 63, 74, 164, 188, 194, 195, 207, 255, 275, 278, 279, 284, 314, 356, 362, 363, 398, 399, 404, 422, 423, 428, 455, 458, 459, 483, 494, 524, 539, 584, 614, 615, 662, 674, 692, 734, 747, 758, 759, 764, 824, 854, 867, 890, 927, 935, 944, 956, 998, 999 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

A000005(a(n)-1) < A000005(a(n)) < A000005(a(n)+1).

MATHEMATICA

Select[Range[2, 1000], DivisorSigma[0, # - 1] < DivisorSigma[0, #] < DivisorSigma[0, # + 1] &] (* T. D. Noe, Apr 05 2011 *)

PROG

(MAGMA) d:=func<k | NumberOfDivisors(k)>; [ n: n in [2..1000] | d(n-1) lt d(n) and d(n) lt d(n+1)];   // Bruno Berselli, Apr 05 2011

CROSSREFS

Cf. A000005, A188540, A075028.

Sequence in context: A143733 A296766 A003635 * A076764 A214251 A031058

Adjacent sequences:  A188628 A188629 A188630 * A188632 A188633 A188634

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Apr 05 2011

EXTENSIONS

Corrected and extended by T. D. Noe, Apr 05 2011

STATUS

approved

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Last modified August 10 08:13 EDT 2020. Contains 336368 sequences. (Running on oeis4.)