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A140578 A positive integer n is included if n is the smallest integer in a run of a plural number of consecutive integers all with the same number of divisors. 1
2, 14, 21, 26, 33, 38, 44, 57, 75, 85, 93, 98, 104, 116, 118, 122, 133, 135, 141, 145, 147, 158, 171, 177, 189, 201, 205, 213, 217, 230, 242, 253, 285, 296, 298, 301, 326, 332, 334, 344, 374, 381, 387, 393, 429, 434, 445, 453, 481, 501, 507, 514, 526, 537, 542 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
All terms of this sequence are included in sequence A005237.
LINKS
EXAMPLE
d(33) = d(34) = d(35), where d(n) is the number of divisors of n. And since d(32) does not equal d(33), d(33) is the first term of this run of similar values. So 33 is included in this sequence.
MATHEMATICA
(First /@ Select[ Split[ Table[ {DivisorSigma[0, n], n}, {n, 1, 600}], First[#1] == First[#2] &] , Length[#] > 1 &])[[All, 2]] (* Jean-François Alcover, Oct 07 2013 *)
CROSSREFS
Cf. A005237.
Sequence in context: A131221 A138047 A005237 * A052213 A280074 A359745
KEYWORD
nonn
AUTHOR
Leroy Quet, Jul 05 2008
EXTENSIONS
Extended by Ray Chandler, Jun 25 2009
STATUS
approved

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Last modified March 19 04:58 EDT 2024. Contains 370952 sequences. (Running on oeis4.)