A105301 Primes formed by reverse concatenation of 7 consecutive triangular numbers.

7140702169036786667065556441, 16110159311575315576154001522515051, 47586472784697146665463604605645753, 55278549465461554285539565362853301

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

a(1)=7140702169036786667065556441 because 7140702169036786667065556441 is the prime formed by reverse concatenation of 7 consecutive triangular numbers i.e. 6441,6555,6670,6786,6903,7021 and 7140.

Mathematica

Select[FromDigits[Flatten[IntegerDigits/@#]]&/@(Reverse/@Partition[ Accumulate[ Range[500]], 7, 1]), PrimeQ] (* Harvey P. Dale, Jul 27 2019 *)

Crossrefs

Sequence in context: A003853 A003846 A375122 * A104300 A095450 A217407

Adjacent sequences: A105298 A105299 A105300 * A105302 A105303 A105304

Keyword

base,nonn

Author

Shyam Sunder Gupta, Apr 25 2005

Status

approved