A222728 Palindromic composite numbers starting with a digit 7.

77, 707, 717, 737, 747, 767, 777, 7007, 7117, 7227, 7337, 7447, 7557, 7667, 7777, 7887, 7997, 70007, 70107, 70307, 70407, 70707, 70807, 70907, 71017, 71117, 71217, 71417, 71517, 71617, 71717, 71817, 72027, 72127, 72327, 72427, 72527, 72627, 72827, 72927, 73137

Offset

1,1

Comments

Subsequence of A032350 (palindromic nonprime numbers) and A002113 (palindromic numbers). Complement of A222727 (palindromic primes starting with a digit 7) with respect to A043042 (palindromic numbers starting with a digit 7).

Links

Jaroslav Krizek, Table of n, a(n) for n = 1..1038

Mathematica

Table[Select[Range[7*10^d, 8*10^d-1], CompositeQ[#]&&PalindromeQ[#]&], {d, 4}]//Flatten (* Harvey P. Dale, Nov 07 2021 *)

Crossrefs

Cf. A032350, A002113, A222727, A043042.

Sequence in context: A027574 A059047 A046149 * A223649 A205434 A125581

Adjacent sequences: A222725 A222726 A222727 * A222729 A222730 A222731

Keyword

nonn,base

Author

Jaroslav Krizek, Mar 09 2013

Status

approved