

A202262


Composite numbers in which all substrings are composite.


8



4, 6, 8, 9, 44, 46, 48, 49, 64, 66, 68, 69, 84, 86, 88, 94, 96, 98, 99, 444, 446, 448, 464, 466, 468, 469, 484, 486, 488, 494, 496, 498, 644, 646, 648, 649, 664, 666, 668, 669, 684, 686, 688, 694, 696, 698, 699, 844, 846, 848, 849, 864, 866, 868, 869, 884, 886
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OFFSET

1,1


COMMENTS

Subsequence of A062115, A202260, A029581.
Supersequence of A202265.
This is a 10automatic sequence, see A071062.  Charles R Greathouse IV, Jan 01 2012


LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..10000
Rémy Sigrist, PARI program for A202262
Index entries for 10automatic sequences


MATHEMATICA

sub[n_] := Block[{d = IntegerDigits[n]}, Union@ Reap[ Do[Sow@ FromDigits@ Take[d, {i, j}], {j, Length@ d}, {i, j}]][[2, 1]]]; Select[ Range@ 900, Union[{4, 6, 8, 9}, IntegerDigits[#]] == {4, 6, 8, 9} && AllTrue[sub[#], CompositeQ] &] (* Giovanni Resta, Dec 20 2019 *)


PROG

(PARI) See Links section.


CROSSREFS

Cf. A085823 (primes in which all substrings are primes), A068669 (noncomposite numbers in which all substrings are noncomposite), A062115 (nonprimes in which all substrings are nonprimes).
Cf. A010051.
Sequence in context: A113624 A113591 A029581 * A202266 A232541 A076612
Adjacent sequences: A202259 A202260 A202261 * A202263 A202264 A202265


KEYWORD

nonn,base


AUTHOR

Jaroslav Krizek, Dec 25 2011


EXTENSIONS

Data corrected by Reinhard Zumkeller, May 05 2012
Data corrected by Rémy Sigrist, Dec 19 2019
Incorrect Haskell program deleted by M. F. Hasler, Dec 20 2019


STATUS

approved



