

A083676


Triangular numbers whose sum of aliquot divisors is a prime number.


1



21, 55, 171, 325, 595, 741, 1081, 1711, 2485, 3081, 3655, 7021, 11325, 13861, 14365, 15931, 23005, 23653, 23871, 29403, 31375, 32131, 44551, 45451, 48205, 52003, 53301, 60031, 65341, 65703, 67161, 74691, 81003, 87571, 92665, 108811, 110215, 114481, 115921
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OFFSET

1,1


LINKS

Donovan Johnson, Table of n, a(n) for n = 1..1000
Shyam Sunder Gupta, Fascinating Triangular Numbers.


EXAMPLE

a(2) = 55 because sum of aliquot divisors of 55 = 1+5+11 = 17, which is a prime number.


PROG

(PARI) c=0; for(m=1, 34021, t=m*(m+1)\2; if(isprime(sigma(t)t), c++; write("b083676.txt", c " " t))) /* Donovan Johnson, May 20 2013 */


CROSSREFS

Sequence in context: A144302 A180674 A067431 * A264104 A236694 A292368
Adjacent sequences: A083673 A083674 A083675 * A083677 A083678 A083679


KEYWORD

nonn


AUTHOR

Shyam Sunder Gupta, Jun 15 2003


STATUS

approved



