A014303 a(n) = prime(n)*(prime(n+1)-1)/2.

2, 6, 15, 35, 66, 104, 153, 209, 322, 435, 558, 740, 861, 989, 1222, 1537, 1770, 2013, 2345, 2556, 2847, 3239, 3652, 4272, 4850, 5151, 5459, 5778, 6104, 7119, 8255, 8908, 9453, 10286, 11175, 11778, 12717

Offset

1,1

Links

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

Formula

a(n) = A000040(n)*A005097(n). - Omar E. Pol, Sep 14 2013

Mathematica

(#[[1]](#[[2]]-1))/2&/@Partition[Prime[Range[40]], 2, 1] (* Harvey P. Dale, Jan 13 2014 *)

Prog

(PARI) vector(40, n, prime(n)*(prime(n+1)-1)/2) \\ G. C. Greubel, Jun 12 2019
(Magma) [NthPrime(n)*(NthPrime(n+1)-1)/2: n in [1..40]]; // G. C. Greubel, Jun 12 2019
(Sage) [nth_prime(n)*(nth_prime(n+1)-1)/2 for n in (1..40)] # G. C. Greubel, Jun 12 2019

Crossrefs

Cf. A000040, A005097, A014302.

Sequence in context: A340779 A073838 A337646 * A076060 A126764 A272340

Adjacent sequences: A014300 A014301 A014302 * A014304 A014305 A014306

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved