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A076156 Numbers n such that Omega(n+1) = Omega(n)+1, where Omega(m) (A001222) denotes the number of prime factors of m, counting multiplicity. 3
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; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A079890(a(n)) = a(n)+1. - Reinhard Zumkeller, Feb 01 2008

LINKS

R. Zumkeller, Table of n, a(n) for n = 1..1000

FORMULA

a(n) seems to be asymptotic to c*n where c=7.6.... - Benoit Cloitre, Jan 15 2003

EXAMPLE

Omega(26 + 1) = 3 = 1 + 2 = 1 + Omega(26), so 26 is a term of the sequence.

MATHEMATICA

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

Position[Partition[PrimeOmega[Range[400]], 2, 1], _?(#[[1]]+1==#[[2]]&), 1, Heads->False]//Flatten (* Harvey P. Dale, May 15 2018 *)

CROSSREFS

Sequence in context: A026720 A026003 A103792 * A141630 A289467 A289533

Adjacent sequences:  A076153 A076154 A076155 * A076157 A076158 A076159

KEYWORD

easy,nonn

AUTHOR

Joseph L. Pe, Nov 01 2002

STATUS

approved

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Last modified October 13 23:52 EDT 2019. Contains 327983 sequences. (Running on oeis4.)