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A202265
Nonprime numbers in which all substrings and reversal substrings are nonprimes.
7
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
1,3
COMMENTS
Subsequence of A062115, A202259.
Supersequence of A202266.
LINKS
EXAMPLE
All substrings and reversal substrings of 186 are nonprimes: 1, 6, 8, 18, 68, 81, 86, 186, 681.
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 *)
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).
Sequence in context: A072362 A278948 A084988 * A004716 A212372 A372308
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Dec 25 2011
EXTENSIONS
Corrected (498 deleted) by Harvey P. Dale, Jul 30 2024
STATUS
approved