A100688 a(n) = prime(n) * 3^prime(n) - 1.

17, 80, 1214, 15308, 1948616, 20726198, 2195382770, 22082967872, 2165293113020, 1990280943581606, 19147875284802356, 16660504517966902430, 1495392851464002242522, 14115049597965094337960, 1249674274871002654525988, 1027312020387041054530226318

Offset: 1

Author

Parthasarathy Nambi, Dec 07 2004

Keywords

• nonn

Examples

			a(1) = 2*3^2 - 1 = 17.
		

Crossrefs

Cf. A060352.

Programs

Magma

[NthPrime(n)*3^NthPrime(n) - 1: n in [1..20]]; // Vincenzo Librandi, Aug 27 2015

Mathematica

Do[Print[Prime[n]*3^(Prime[n]) - 1], {n, 1, 20}] (* Stefan Steinerberger, Feb 15 2006 *)
# 3^#-1&/@Prime[Range[20]] (* Harvey P. Dale, Jan 24 2012 *)

Extensions

More terms from Stefan Steinerberger, Feb 15 2006

a(15)-a(16) from Vincenzo Librandi, Aug 27 2015