

A346138


Sphenic numbers that are the product of Mersenne primes.


0



651, 2667, 11811, 27559, 172011, 761763, 1777447, 2752491, 3120771, 7281799, 11010027, 12189603, 28442407, 32247967, 48758691, 49938051, 113770279, 116522119, 199753347, 466091143, 516026527, 2064117919, 3220807683, 7515217927, 12883304451, 30061043719, 33281679391, 45097156587, 133127479327
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

The largest known sphenic number is a term of this sequence.
a(n) == 3 (mod 4) for n >= 1.


LINKS

Table of n, a(n) for n=1..29.
Wikipedia, Sphenic number (lists the largest known sphenic number)
Wikipedia, Mersenne prime
Index to sequences related to prime signature


EXAMPLE

a(1) = 651, since 651 = 3*7*31.
a(2) = 2667, since 2667 = 3*7*127.
a(3) = 11811, since 11811 = 3*31*127.


MATHEMATICA

M = 2^MersennePrimeExponent[Range[12]]  1; Take[ Union[ Times @@@ Subsets[ M, {3}]], 50]


CROSSREFS

Cf. A007304, A046528, A144856.
Sequence in context: A043605 A255619 A151736 * A010087 A110850 A257715
Adjacent sequences: A346135 A346136 A346137 * A346139 A346140 A346141


KEYWORD

nonn


AUTHOR

Timothy L. Tiffin, Jul 06 2021


STATUS

approved



