OFFSET
1,2
COMMENTS
These numbers play a crucial role in inverting Euler's totient function.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
S. Contini, E. Croot, I. E. Shparlinski, Complexity of Inverting the Euler Function, arXiv:math/0404116 [math.NT], 2004.
EXAMPLE
18 is an element of the sequence because 18=(3-1)3^2 and 3 is a prime.
MAPLE
N:= 1000: # for terms <= N
S:= {}: R:= NULL:
p:= 1:
while p <= N do
p:= nextprime(p);
S:= S union {seq((p-1)*p^k, k = 0..ilog[p](N/(p-1)))};
R:= R, seq((p-1)*p^k, k = 0..ilog[p](N/(p-1)))
od:
sort(convert(S, list)); # Robert Israel, Feb 10 2021
MATHEMATICA
Take[Union@ Flatten@ Table[(Prime[n] - 1)Prime[n]^k, {n, 60}, {k, 0, 7}], 61] (* Robert G. Wilson v, Jan 05 2006 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Franz Vrabec, Jan 03 2006
EXTENSIONS
More terms from Robert G. Wilson v, Jan 05 2006
STATUS
approved