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Search: id:A076156
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| A076156 |
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Numbers n such that Omega(n+1) = Omega(n)+1, where Omega(m) (A001222) denotes the number of prime factors of m, counting multiplicity. |
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+0
2
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| 1, 3, 5, 13, 26, 37, 49, 51, 61, 62, 65, 69, 73, 74, 77, 91, 99, 115, 123, 125, 129, 146, 157, 169, 185, 187, 188, 193, 194, 195, 206, 221, 231, 235, 237, 254, 265, 267, 274, 275, 277, 278, 289, 291, 309, 313, 321, 343, 355, 362, 363, 365, 374, 386, 397, 398
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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A079890(a(n)) = a(n)+1. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 01 2008
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LINKS
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R. Zumkeller, Table of n, a(n) for n = 1..1000
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FORMULA
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a(n) seems to be asymptotic to c*n where c=7.6.... - Benoit Cloitre (benoit7848c(AT)orange.fr), Jan 15 2003
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EXAMPLE
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Omega(26 + 1) = 3 = 1 + 2 = 1 + Omega(26), so 26 is a term of the sequence.
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MATHEMATICA
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Omega[n_] := Apply[Plus, Transpose[FactorInteger[n]][[2]]]; l = {1}; Do[ If[Omega[i + 1] == Omega[i] + 1, l = Append[l, i]], {i, 2, 10^3}]; l
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CROSSREFS
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Sequence in context: A026720 A026003 A103792 this_sequence A141630 A084173 A000631
Adjacent sequences: A076153 A076154 A076155 this_sequence A076157 A076158 A076159
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KEYWORD
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easy,nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Nov 01 2002
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