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A129767 Interleaved primes and semiprimes. 1
2, 4, 3, 6, 5, 9, 7, 10, 11, 14, 13, 15, 17, 21, 19, 22, 23, 25, 29, 26, 31, 33, 37, 34, 41, 35, 43, 38, 47, 39, 53, 46, 59, 49, 61, 51, 67, 55, 71, 57, 73, 58, 79, 62, 83, 65, 89, 69, 97, 74, 101, 77, 103, 82, 107, 85, 109, 86, 113, 87, 127, 91, 131, 93, 137, 94, 139, 95, 149 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..10000 (first 1000 terms from Harvey P. Dale)
FORMULA
a(2*n-1) = A000040(n), a(2*n) = A001358(n).
MATHEMATICA
Module[{nn=200, pr, sp, len}, pr=Prime[Range[PrimePi[nn]]]; sp=Select[Range[ nn], PrimeOmega[#]==2&]; len=Min[Length[pr], Length[sp]]; Thread[{Take[ pr, len], Take[ sp, len]}]]//Flatten (* Harvey P. Dale, Jun 02 2020 *)
CROSSREFS
Sequence in context: A281120 A246682 A143691 * A119618 A113321 A271647
KEYWORD
easy,less,nonn
AUTHOR
Jonathan Vos Post, Jun 02 2007
STATUS
approved

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Last modified March 1 22:23 EST 2024. Contains 370443 sequences. (Running on oeis4.)