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 A329294 Numbers whose digits are in nondecreasing order in bases 4 and 5. 6
 0, 1, 2, 3, 6, 7, 31, 43, 63, 343 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS There are no more terms through 10^10000 (which is a 16610-digit number in base 4 and a 14307-digit number in base 5). But can it be proved that 343 is the final term of the sequence? LINKS Table of n, a(n) for n=1..10. EXAMPLE a(1) = 0 = 0_4 = 0_5 a(2) = 1 = 1_4 = 1_5 a(3) = 2 = 2_4 = 2_5 a(4) = 3 = 3_4 = 3_5 a(5) = 6 = 12_4 = 11_5 a(6) = 7 = 13_4 = 12_5 a(7) = 31 = 133_4 = 111_5 a(8) = 43 = 223_4 = 133_5 a(9) = 63 = 333_4 = 223_5 a(10) = 343 = 11113_4 = 2333_5 PROG (PARI) isnondec(v) = (#v==0) || (#select(x->(x<0), vector(#v-1, k, v[k+1]-v[k])) == 0); isok(n) = isnondec(digits(n, 4)) && isnondec(digits(n, 5)); \\ Michel Marcus, Nov 11 2019 CROSSREFS Intersection of A023746 (base 4) and A023747 (base 5). Numbers whose digits are in nondecreasing order in bases b and b+1: this sequence (b=4), A329295 (b=5), A329296 (b=6), A329297 (b=7), A329298 (b=8), A329299 (b=9). See A329300 for the (apparently) largest term of each of these sequences. Sequence in context: A159069 A162681 A070301 * A291659 A302090 A088414 Adjacent sequences: A329291 A329292 A329293 * A329295 A329296 A329297 KEYWORD nonn,base AUTHOR Jon E. Schoenfield, Nov 09 2019 STATUS approved

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Last modified September 26 15:38 EDT 2023. Contains 365660 sequences. (Running on oeis4.)