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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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified January 19 15:37 EST 2020. Contains 331049 sequences. (Running on oeis4.)