A092386 Let p(n) = n-th prime; a(n) = largest prime factor of (p(n+1)^2 - p(n)*p(n+2)).

1, 2, 3, 5, 3, 7, 5, 11, 2, 7, 7, 5, 13, 7, 3, 31, 29, 79, 5, 7, 13, 71, 13, 7, 7, 11, 37, 7, 179, 17, 17, 7, 13, 101, 37, 3, 7, 31, 3, 13, 17, 43, 7, 67, 983, 3, 229, 11, 5, 17, 11, 53, 19, 3, 3, 17, 67, 17, 19, 17, 43, 521, 7, 103, 173, 683, 23, 233, 23, 31, 67, 23, 3, 23, 53, 73, 5

Offset: 0

Author

Frank Schwellinger (nummer_eins(AT)web.de), Mar 20 2004

Keywords

• easy
• nonn

Links

• Ivan Neretin, Table of n, a(n) for n = 0..9999

Crossrefs

Cf. A006530, A056221.

Programs

Mathematica

Table[ FactorInteger[Prime[n + 1]^2 - Prime[n]Prime[n + 2]][[ -1, 1]], {n, 80}] (* Robert G. Wilson v, Mar 24 2004 *)

Formula

a(n) = A006530(A056221(n)).

Extensions

More terms from Robert G. Wilson v, Mar 24 2004