A328359 Numbers k such that Omega(k - 2) = Omega(k) = Omega(k + 2) where Omega = A001222.
5, 68, 93, 121, 143, 172, 185, 188, 203, 215, 217, 219, 244, 284, 289, 301, 303, 321, 342, 393, 404, 413, 415, 428, 436, 471, 490, 517, 535, 570, 581, 604, 669, 687, 697, 788, 791, 815, 858, 870, 892, 1014, 1057, 1079, 1135, 1137, 1139, 1147, 1167, 1205, 1206, 1208, 1210, 1255, 1268, 1276
Offset: 1
Keywords
Examples
5 is a term because A001222(3) = A001222(5) = A001222(7) = 1; 68 is a term because A001222(66) = A001222(68) = A001222(70) = 3; 93 is a term because A001222(91) = A001222(93) = A001222(95) = 2.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Programs
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Magma
[k: k in [4..1300]| forall{m:m in [-2,2]| &+[p[2]: p in Factorization(k+m)] eq &+[p[2]: p in Factorization(k)] }]; // Marius A. Burtea, Oct 15 2019 -
Mathematica
Select[Range[10^4],PrimeOmega[#-2]==PrimeOmega[#]==PrimeOmega[#+2]&] (* Metin Sariyar, Oct 14 2019 *) Flatten[Position[Partition[PrimeOmega[Range[2000]],5,1],?(#[[1]]== #[[3]] == #[[5]]&),1,Heads->False]]+2 (* _Harvey P. Dale, Nov 02 2021 *)