A226073 Numbers k such that triangular(k)-1 is a square and triangular(k)+1 is a prime number.

1, 4, 148, 5821348, 13748537282247342677718148, 49900608324196518198677680899235165296598423281799348

Offset

1,2

Comments

a(7) has 191 decimal digits: 314305920...194453348.

Corresponding primes and roots of squares: A226072 and A226074.

Links

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

Crossrefs

Cf. A226069-A226074.

Sequence in context: A160470 A350985 A269136 * A366218 A361774 A294826

Adjacent sequences: A226070 A226071 A226072 * A226074 A226075 A226076

Keyword

nonn

Author

Alex Ratushnyak, May 25 2013

Status

approved