A043042 -id:A043042 - cp's OEIS frontend

A222727 Palindromic primes starting with a digit 7.

7, 727, 757, 787, 797, 70207, 70507, 70607, 71317, 71917, 72227, 72727, 73037, 73237, 73637, 74047, 74747, 75557, 76367, 76667, 77377, 77477, 77977, 78487, 78787, 78887, 79397, 79697, 79997, 7014107, 7035307, 7036307, 7041407, 7046407, 7057507, 7065607, 7069607

Offset: 1

Jaroslav Krizek, Mar 09 2013

Subsequence of A002385 (palindromic primes) and A002113 (palindromic numbers). Complement of A222728 (palindromic composite numbers starting with a digit 7) with respect to A043042 (palindromic numbers starting with a digit 7).

Jaroslav Krizek, Table of n, a(n) for n = 1..1000

Cf. A002385, A002113, A222728, A043042.

Select[Prime[Range[500000]],PalindromeQ[#]&&Mod[#,10]==7&] (* Harvey P. Dale, Nov 22 2022 *)

A222728 Palindromic composite numbers starting with a digit 7.

Original entry on oeis.org

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

Jaroslav Krizek, Mar 09 2013

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).

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

Cf. A032350, A002113, A222727, A043042.

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

A043034 Base-9 palindromes that start with 7.

Original entry on oeis.org

7, 70, 574, 583, 592, 601, 610, 619, 628, 637, 646, 5110, 5200, 5290, 5380, 5470, 5560, 5650, 5740, 5830, 45934, 46015, 46096, 46177, 46258, 46339, 46420, 46501, 46582, 46672, 46753, 46834, 46915, 46996, 47077, 47158

Offset: 1

Clark Kimberling

Cf. A007095, A043078.
Base-9 palindromes: A029955.
Base-9 palindromes that start with d, for d=1..8: A043028..A043035.
Base-b palindromes that start with 7, for b=8..10: A043027, this sequence, A043042.

cp's OEIS Frontend

A222727 Palindromic primes starting with a digit 7.

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A222728 Palindromic composite numbers starting with a digit 7.

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Programs

Mathematica

A043034 Base-9 palindromes that start with 7.

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