login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A064051
a(n) = 2*prime(n)^2 - prime(n+1)^2.
2
-1, -7, 1, -23, 73, 49, 217, 193, 217, 721, 553, 1057, 1513, 1489, 1609, 2137, 3241, 2953, 3937, 4753, 4417, 5593, 5857, 6433, 8617, 9793, 9769, 11017, 10993, 9409, 15097, 15553, 18217, 16441, 21601, 20953, 22729, 25249, 25849, 27817, 31321, 29041, 35713
OFFSET
1,2
COMMENTS
Theorem: a(n) > 0 for all n > 4.
REFERENCES
D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, 1996, Section VII.18, p. 247.
LINKS
FORMULA
a(n) = 2*A001248(n) - A001248(n+1). - Elmo R. Oliveira, Jan 13 2023
MATHEMATICA
Table[2 Prime[n]^2 - Prime[n+1]^2, {n, 45}] (* Vincenzo Librandi, Jun 22 2018 *)
2#[[1]]-#[[2]]&/@Partition[Prime[Range[50]]^2, 2, 1] (* Harvey P. Dale, May 15 2023 *)
PROG
(PARI) a(n) = 2*prime(n)^2 - prime(n + 1)^2; \\ Harry J. Smith, Sep 06 2009
(Magma) [2*NthPrime(n)^2 - NthPrime(n+1)^2: n in [1..45]]; // Vincenzo Librandi, Jun 22 2018
CROSSREFS
Sequence in context: A261248 A214686 A211790 * A147385 A147347 A183109
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Oct 15 2001
STATUS
approved