

A228453


Numbers n such that tau(n+1)  tau(n) = 5, where tau(n) = the number of divisors of n (A000005).


2



35, 169, 289, 529, 961, 1369, 2809, 3135, 4489, 7921, 9409, 10609, 10815, 11881, 12769, 16129, 18495, 18769, 22201, 22801, 26569, 27889, 32041, 33855, 38809, 44521, 49729, 51529, 52441, 53823, 58081, 61503, 69169, 72361, 76729, 78961, 80089, 96721
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OFFSET

1,1


COMMENTS

Numbers n such that A051950(n+1) = 5.
Numbers n such that A049820(n)  A049820(n+1) = 4.


LINKS

Table of n, a(n) for n=1..38.


EXAMPLE

35 is in sequence because tau(36)  tau(35) = 9  4 = 5.


MATHEMATICA

Select[ Range[ 50000], DivisorSigma[0, # ] + 5 == DivisorSigma[0, # + 1] &]


CROSSREFS

Cf. A055927 (numbers n such that tau(n+1)  tau(n) = 1), A230115 (numbers n such that tau(n+1)  tau(n) = 2), A230653 (numbers n such that tau(n+1)  tau(n) = 3), A230654 (numbers n such that tau(n+1)  tau(n) = 4), A000005.
Sequence in context: A015219 A195545 A270860 * A327651 A319042 A033851
Adjacent sequences: A228450 A228451 A228452 * A228454 A228455 A228456


KEYWORD

nonn


AUTHOR

Jaroslav Krizek, Nov 03 2013


STATUS

approved



