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A154729 Products of three distinct primes of the form 6*n + 1 (see A002476). 6
1729, 2821, 3367, 3913, 4123, 4921, 5551, 5719, 6097, 6643, 7189, 7657, 8029, 8113, 8827, 8911, 9139, 9331, 9373, 9709, 9919, 10507, 10621, 11137, 11557, 12649, 12901, 13237, 13699, 13741, 14287, 14497, 14539, 14833, 14911, 15067, 15799, 15841 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Note that a(1) = 1729 is the Hardy-Ramanujan number (see taxicab numbers in A001235, A011541).

Equivalently, products of three distinct primes of the form 3*n + 1. - Omar E. Pol, Feb 17 2018

LINKS

Table of n, a(n) for n=1..38.

G. L. Honaker, Jr. and Chris Caldwell, Prime Curios!, Number 1729.

EXAMPLE

The first three primes of the form 6*n + 1 are 7, 13 and 19, so a(1) = 7*13*19 = 1729. - Omar E. Pol, Feb 17 2018

MATHEMATICA

Module[{nn=40, prs}, prs=Select[6*Range[nn]+1, PrimeQ]; Take[Times@@@ Subsets[ prs, {3}]//Union, nn]] (* Harvey P. Dale, Feb 17 2018 *)

CROSSREFS

Cf. A001235, A002476, A011541, A154716, A154717, A154728.

Sequence in context: A033181 A300949 A198775 * A083737 A182208 A324316

Adjacent sequences:  A154726 A154727 A154728 * A154730 A154731 A154732

KEYWORD

nonn

AUTHOR

Omar E. Pol, Jan 18 2009

EXTENSIONS

a(5)-a(38) from Donovan Johnson, Jan 28 2009

STATUS

approved

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Last modified July 17 14:44 EDT 2019. Contains 325106 sequences. (Running on oeis4.)