A014686 In sequence of prime numbers add 1 to first prime, 3rd prime, fifth prime, ... then subtract 1 from 2nd prime, fourth prime, sixth prime and so on.

3, 2, 6, 6, 12, 12, 18, 18, 24, 28, 32, 36, 42, 42, 48, 52, 60, 60, 68, 70, 74, 78, 84, 88, 98, 100, 104, 106, 110, 112, 128, 130, 138, 138, 150, 150, 158, 162, 168, 172, 180, 180, 192, 192, 198, 198, 212, 222, 228, 228, 234, 238, 242, 250, 258, 262, 270, 270

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

a(n)=prime(n)-(-1)^n=A000040(n)-A033999(n+1). [From Juri-Stepan Gerasimov, Sep 11 2009]

Mathematica

Module[{nn=60}, Total/@Partition[Riffle[Prime[Range[nn]], {1, -1}, {2, -1, 2}], 2]] (* Harvey P. Dale, Oct 04 2019 *)

Crossrefs

Sequence in context: A096375 A062200 A114208 * A053090 A264400 A365660

Adjacent sequences: A014683 A014684 A014685 * A014687 A014688 A014689

Keyword

nonn,easy

Author

Mohammad K. Azarian

Extensions

More terms from Andrew J. Gacek (andrew(AT)dgi.net)

Status

approved