A202265 Nonprime numbers in which all substrings and reversal substrings are nonprimes.

0, 1, 4, 6, 8, 9, 10, 18, 40, 44, 46, 48, 49, 60, 64, 66, 68, 69, 80, 81, 84, 86, 88, 90, 94, 96, 99, 100, 108, 180, 184, 186, 400, 404, 406, 408, 440, 444, 446, 448, 460, 464, 466, 468, 469, 480, 481, 484, 486, 488, 490, 494, 496, 600, 604, 606, 608, 609

Offset: 1

Author

Jaroslav Krizek, Dec 25 2011

Keywords

• nonn
• base

Comments

Subsequence of A062115, A202259.

Supersequence of A202266.

Examples

			All substrings and reversal substrings of 186 are nonprimes: 1, 6, 8, 18, 68, 81, 86, 186, 681.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..2000

Crossrefs

Cf. A202263 (primes in which all substrings and reversal substrings are primes), A068669 (noncomposite numbers in which all substrings and reversal substrings are noncomposites), A202266 (composite numbers in which all substrings and reversal substrings are composites).

Programs

Mathematica

Select[Range[0,1000],NoneTrue[Union[Flatten[{#,IntegerReverse[#]}&/@Flatten[Table[ FromDigits/@Partition[IntegerDigits[#],d,1],{d,IntegerLength[#]}]]]],PrimeQ]&] (* Harvey P. Dale, Jul 30 2024 *)

Extensions

Corrected (498 deleted) by Harvey P. Dale, Jul 30 2024