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

Author

Shyam Sunder Gupta, Apr 17 2005

Keywords

• base
• nonn

Examples

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

Links

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

Crossrefs

These are the primes in A246972.

Cf. A104242, A104302, A104303, A104304.

Programs

Mathematica

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

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