A036878 a(n) = p^(p-1) where p = prime(n).

2, 9, 625, 117649, 25937424601, 23298085122481, 48661191875666868481, 104127350297911241532841, 907846434775996175406740561329, 88540901833145211536614766025207452637361, 550618520345910837374536871905139185678862401

Offset

1,1

Comments

Also the least refactorable number (A033950) that has the n-th prime as its least prime factor. - Robert G. Wilson v, Jun 28 2006

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..77

S. Colton, Refactorable Numbers - A Machine Invention, J. Integer Sequences, Vol. 2, 1999, #2.

S. Colton, HR - Automatic Theory Formation in Pure Mathematics

Example

5^(5-1) = 5^4 = 625.

Mathematica

Table[Prime@n^(Prime@n - 1), {n, 10}] (* Robert G. Wilson v, Jun 28 2006 *)
#^(#-1)&/@Prime[Range[10]] (* Harvey P. Dale, Oct 23 2015 *)

Prog

(Magma) [p^(p-1): p in PrimesUpTo(50)]; // Vincenzo Librandi, Mar 27 2014
(PARI) a(n) = my(p=prime(n)); p^(p-1); \\ Michel Marcus, Jan 24 2019

Crossrefs

These integers are refactorable -- i.e., the number of divisors divides the number itself, cf. A033950.

Subset of A062981. Subsequence of A000169.

Subsequence of A111134 and A246655.

Sequence in context: A085605 A336247 A180936 * A162710 A249903 A008322

Adjacent sequences: A036875 A036876 A036877 * A036879 A036880 A036881

Keyword

nonn,easy

Author

Simon Colton (simonco(AT)cs.york.ac.uk)

Status

approved