A244369 Palindromic right-angled primes.

101, 787, 34543, 7654567, 345676543, 34567876543

Offset: 1

Author

Omar E. Pol, Jun 26 2014

Keywords

• nonn
• base
• fini
• full

Comments

Intersection of A002113 and A167842.

Intersection of A002385 and A135602.

The last term of this sequence is also the last term of A134811.

Examples

			Illustration of a(6) = 34567876543, the last term of this sequence:
. . . . . . . . . . .
. . . . . 8 . . . . .
. . . . 7 . 7 . . . .
. . . 6 . . . 6 . . .
. . 5 . . . . . 5 . .
. 4 . . . . . . . 4 .
3 . . . . . . . . . 3
. . . . . . . . . . .
. . . . . . . . . . .
. . . . . . . . . . .
		

Crossrefs

Cf. A000040, A002113, A002385, A134811, A135602, A167842.

Programs

Python

from sympy import isprime
A244369 = []
for n in range(1,10):
    for m in range(n-1,-1,-1):
        l = ''.join([str(d) for d in range(n,m-1,-1)])
        p = int(l+l[-2::-1])
        if isprime(p):
            A244369.append(p)
    for m in range(n+1,10):
        l = ''.join([str(d) for d in range(n,m+1)])
        p = int(l+l[-2::-1])
        if isprime(p):
            A244369.append(p)
A244369 = sorted(A244369) # Chai Wah Wu, Aug 15 2014