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A119728 Primes p such that p+1, p+2, p+3 and p+4 have equal number of divisors. 4
241, 13781, 19141, 21493, 50581, 61141, 76261, 77431, 94261, 95383, 95413, 98101, 104743, 104869, 134581, 141653, 142453, 152629, 153991, 158341, 160933, 165541, 169111, 199831, 201511, 203431, 206551, 229351, 233941, 235111, 253013, 273367 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

241 is a term since 242, 243, 244 and 245 all have 6 divisors:

{1,2,11,22,121,242},{1,3,9,27,81,243},{1,2,4,61,122,244} and {1,5,7,35,49,245}.

MATHEMATICA

Select[Prime@Range@50000, DivisorSigma[0, #+1]==DivisorSigma[0, #+2]==DivisorSigma[0, #+3]==DivisorSigma[0, #+4]&]

CROSSREFS

Cf. A008329, A049234, A119705, A119711, A119730, A119740.

Sequence in context: A007205 A008349 A094732 * A133327 A001361 A206842

Adjacent sequences:  A119725 A119726 A119727 * A119729 A119730 A119731

KEYWORD

nonn

AUTHOR

Zak Seidov, Jul 29 2006

STATUS

approved

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Last modified September 18 02:19 EDT 2020. Contains 337164 sequences. (Running on oeis4.)