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 A256291 Numbers which have only digits 5 and 6 in base 10. 16

%I

%S 5,6,55,56,65,66,555,556,565,566,655,656,665,666,5555,5556,5565,5566,

%T 5655,5656,5665,5666,6555,6556,6565,6566,6655,6656,6665,6666,55555,

%U 55556,55565,55566,55655,55656,55665,55666,56555,56556

%N Numbers which have only digits 5 and 6 in base 10.

%H Vincenzo Librandi, <a href="/A256291/b256291.txt">Table of n, a(n) for n = 1..8190</a>

%H <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>.

%F a(n) = A007931(n) + A002278(A000523(n+1)) = A256290(n) + A256077(n) etc.

%t Flatten[Table[FromDigits[#,10]&/@Tuples[{5,6},n],{n,5}]]

%o (MAGMA) [n: n in [1..60000] | Set(IntegerToSequence(n, 10)) subset {5, 6}];

%o (PARI) A256291(n)=vector(#n=binary(n+1)[2..-1],i,10^(#n-i))*n~+10^#n\9*5

%o (MAGMA) [n: n in [1..100000] | Set(Intseq(n)) subset {5,6}]; // :Vincenzo Librandi_, Aug 19 2016

%Y Cf. A007088 (digits 0 & 1), A007931 (digits 1 & 2), A032810 (digits 2 & 3), A032834 (digits 3 & 4), A256290 (digits 4 & 5), A256292 (digits 6 & 7), A256340 (digits 7 & 8), A256341 (digits 8 & 9).

%K nonn,base,easy

%O 1,1

%A _M. F. Hasler_, Mar 27 2015

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Last modified August 14 19:09 EDT 2020. Contains 336483 sequences. (Running on oeis4.)