A244369 Palindromic right-angled primes.

101, 787, 34543, 7654567, 345676543, 34567876543

Offset

1,1

Comments

Intersection of A002113 and A167842.

Intersection of A002385 and A135602.

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

Links

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

Example

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

Prog

(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

Crossrefs

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

Sequence in context: A171813 A089291 A167842 * A200733 A267002 A242138

Adjacent sequences: A244366 A244367 A244368 * A244370 A244371 A244372

Keyword

nonn,base,fini,full

Author

Omar E. Pol, Jun 26 2014

Status

approved