A197422 Primes of the form sum_{j=1..n} (-1)^j *prime(j)*prime(j+1).

1103, 9281, 10949, 12157, 26921, 48757, 61949, 87407, 92459, 95923, 124087, 162859, 198811, 289417, 363809, 467183, 530983, 754981, 792307, 830677, 1124051, 1537373, 1662307, 1706251, 1830401, 2023183, 2507963, 2534879, 3358099, 3616721, 3912901, 3929707

Offset

1,1

Comments

We select primes in the alternating partial sums of A006094 (which start -6, 9, -26, 51, -92, 129, -194, 243,...).

The corresponding values of n are 14, 32, 34, 36, 50, 64, 70, 80,...

Links

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

Example

For n = 14, a(1) = 1103 = - 2*3 + 3*5 - 5*7 + ....+ 43*47 where 43 = prime(14) and 47 = prime(15).

Maple

p:=0:for n from 1 to 500 do:p:=p+((-1)^n)* ithprime(n)*ithprime(n+1):if type(p, prime)=true then printf(`%d, `, p): else fi:od:

Mathematica

Select[Accumulate[Times@@@Partition[Riffle[Times@@@Partition[ Prime[ Range[ 500]], 2, 1], {-1, 1}, {2, -1, 2}], 2]], PrimeQ] (* Harvey P. Dale, Feb 17 2015 *)

Crossrefs

Cf. A197421.

Sequence in context: A271431 A272754 A060519 * A291134 A233563 A127308

Adjacent sequences: A197419 A197420 A197421 * A197423 A197424 A197425

Keyword

nonn

Author

Michel Lagneau, Oct 14 2011

Status

approved