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 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Subsequence of A062115, A202260, A029581. Supersequence of A202265. This is a 10-automatic 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 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

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Last modified August 3 04:30 EDT 2020. Contains 336197 sequences. (Running on oeis4.)