A077652 -id:A077652 - cp's OEIS frontend

A227858 Numbers which start and end with the same digit in decimal.

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 303, 313, 323, 333, 343, 353, 363, 373, 383, 393, 404, 414, 424, 434, 444, 454, 464, 474, 484, 494, 505, 515, 525, 535, 545, 555, 565, 575, 585, 595, 606, 616, 626

Offset: 1

Brian E. Foose and Todd R. Haldeman, Nov 01 2013

Supersequence of A002113 and A208259.
The first term that is not a palindromic number is a(109) = 1011. - Alonso del Arte, Nov 01 2013
Primes in this sequence are A077652. - Jonathan Vos Post, Nov 02 2013
Differs from A110751 which contains for example 1089. - R. J. Mathar, Jun 29 2025

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Cf. A002113, A077652, A208259.

Select[Range[700],IntegerDigits[#][[1]]==IntegerDigits[#][[-1]]&] (* Harvey P. Dale, Nov 28 2019 *)

is(n)=n=digits(n);n[1]==n[#n] \\ Charles R Greathouse IV, Nov 01 2013

a(n) = 10n + O(1). - Charles R Greathouse IV, Nov 01 2013

A231278 Not necessarily palindromic primes of which initial and terminal digits are identical, as written in base 3.

Original entry on oeis.org

2, 111, 212, 1011, 1101, 1121, 2012, 2122, 10121, 10211, 11001, 11201, 12011, 12121, 12211, 20012, 20102, 20122, 21002, 21022, 22102, 22122, 22212, 101001, 101021, 101111, 102101, 102121, 110021, 110111, 110221, 111121, 111211, 112001, 112201, 120011, 120121

Offset: 1

Jonathan Vos Post, Nov 06 2013

Base-3 analog of what A077652 is for base 10.

			a(3) = 212, which starts and ends with "2", and in base 3 means 2*(3^2) + 1*(3^1) + 2*(3^0) = 18 + 3 + 2 = 23 (base 10), which is prime.

Harvey P. Dale, Table of n, a(n) for n = 1..2500

Cf. A000030, A000040, A007089, A077652, A227858.

FromDigits/@Select[IntegerDigits[#,3]&/@Prime[Range[100]],#[[1]]==#[[-1]]&] (* Harvey P. Dale, Oct 23 2022 *)

More terms from Alois P. Heinz, Nov 07 2013

cp's OEIS Frontend

A227858 Numbers which start and end with the same digit in decimal.

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