A121914 Numbers n such that (partial sums of n times (n 1's)) + 1 is prime; or n such that Sum_{k=1..n} A053422(k) + 1 is prime.

1, 4, 15, 31, 424, 895

Offset

1,2

Comments

Also, numbers n such that (20+20*(9*n-1)*10^n-81*(n^2+n))/1458 + 1 is prime.

Links

Table of n, a(n) for n=1..6.

Crossrefs

Sequence in context: A188075 A322740 A366659 * A336607 A321490 A270710

Adjacent sequences: A121911 A121912 A121913 * A121915 A121916 A121917

Keyword

more,nonn

Author

Jason Earls, Sep 02 2006

Status

approved