A163294 a(n) = 2 + Sum_{x=n..prime(n)} (-x*(-1)^x).

1, 3, 6, 4, 10, 6, 14, 8, 18, 12, 23, 15, 29, 17, 33, 21, 40, 24, 45, 28, 49, 31, 55, 35, 63, 40, 67, 42, 71, 44, 81, 52, 87, 55, 94, 60, 99, 65, 105, 69, 112, 72, 119, 77, 123, 79, 131, 90, 140, 92, 144, 96, 149, 101, 158, 106, 165, 109, 170, 113, 174, 118, 187, 126, 191

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Example

a(1) = 2 + 1 - 2 = 1;
a(2) = 2 - 2 + 3 = 3;
a(3) = 2 + 3 - 4 + 5 = 6;
a(4) = 2 - 4 + 5 - 6 + 7 = 4;
a(5) = 2 + 5 - 6 + 7 - 8 + 9 - 10 + 11 = 10.

Maple

A163294 := proc(n) 2+add( -j*(-1)^j, j=n..ithprime(n)) ; end: seq(A163294(n), n=1..120) ; # R. J. Mathar, Oct 10 2009

Mathematica

Table[2 + Sum[k*(-1)^(k + 1), {k, n, Prime[n]}], {n, 1, 100}] (* G. C. Greubel, Dec 17 2016 *)

Prog

(PARI) for(n=1, 50, print1(2 + sum(k=n, prime(n), k*(-1)^(k+1)), ", ")) \\ G. C. Greubel, Dec 17 2016

Crossrefs

Cf. A000027, A000040.

Sequence in context: A242224 A294671 A275985 * A168577 A122634 A169846

Adjacent sequences: A163291 A163292 A163293 * A163295 A163296 A163297

Keyword

nonn,less

Author

Juri-Stepan Gerasimov, Jul 24 2009

Extensions

Corrected by Juri-Stepan Gerasimov, Jul 26 2009

Edited (but not checked) by N. J. A. Sloane, Jul 27 2009

Roughly 50 percent of the entries corrected by R. J. Mathar, Oct 10 2009

Status

approved