A104301 Primes which are the reverse concatenation of two consecutive square numbers.

41, 6449, 196169, 576529, 11561089, 14441369, 27042601, 38443721, 51845041, 60845929, 67246561, 84648281, 1081610609, 2073620449, 2190421609, 2822427889, 3240032041, 4000039601, 4326442849, 5017649729, 5290052441, 6250062001, 7507674529, 8294482369, 103684103041

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

The first term is 41 which is a prime and is the reverse concatenation of 1 and 4 which are two consecutive square numbers.

Mathematica

cat[s_] := FromDigits[Flatten[IntegerDigits[s]]]; Select[cat /@ Reverse /@ Partition[Range[350]^2, 2, 1], PrimeQ] (* Amiram Eldar, Jul 15 2025 *)

Prog

(Python)
from sympy import isprime
A104301_list = []
for n in range(1, 2000):
    x = int(str((n+1)**2)+str(n**2))
    if isprime(x):
        A104301_list.append(x) # Chai Wah Wu, Sep 13 2014

Crossrefs

These are the primes in A246972.

Cf. A104242, A104302, A104303, A104304.

Sequence in context: A091758 A208255 A221325 * A221300 A221377 A160477

Adjacent sequences: A104298 A104299 A104300 * A104302 A104303 A104304

Keyword

base,nonn

Author

Shyam Sunder Gupta, Apr 17 2005

Status

approved