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

5, 6, 55, 56, 65, 66, 555, 556, 565, 566, 655, 656, 665, 666, 5555, 5556, 5565, 5566, 5655, 5656, 5665, 5666, 6555, 6556, 6565, 6566, 6655, 6656, 6665, 6666, 55555, 55556, 55565, 55566, 55655, 55656, 55665, 55666, 56555, 56556

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..8190

Index entries for 10-automatic sequences.

Formula

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

Mathematica

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

Prog

(Magma) [n: n in [1..60000] | Set(IntegerToSequence(n, 10)) subset {5, 6}];
(PARI) A256291(n)=vector(#n=binary(n+1)[2..-1], i, 10^(#n-i))*n~+10^#n\9*5
(Magma) [n: n in [1..100000] | Set(Intseq(n)) subset {5, 6}]; // Vincenzo Librandi, Aug 19 2016

Crossrefs

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).

Sequence in context: A396309 A385325 A157805 * A299243 A191557 A223530

Adjacent sequences: A256288 A256289 A256290 * A256292 A256293 A256294

Keyword

nonn,base,easy

Author

M. F. Hasler, Mar 27 2015

Status

approved