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A256340 Numbers which have only digits 7 and 8 in base 10. 10
7, 8, 77, 78, 87, 88, 777, 778, 787, 788, 877, 878, 887, 888, 7777, 7778, 7787, 7788, 7877, 7878, 7887, 7888, 8777, 8778, 8787, 8788, 8877, 8878, 8887, 8888, 77777, 77778, 77787, 77788, 77877, 77878, 77887, 77888, 78777, 78778 (list; graph; refs; listen; history; text; internal format)
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) + A002280(A000523(n+1)) = A256292(n) + A256077(n) etc.

MATHEMATICA

Flatten[Table[FromDigits[#, 10]&/@Tuples[{7, 8}, n], {n, 5}]]

PROG

(MAGMA) [n: n in [1..35000] | Set(IntegerToSequence(n, 10)) subset {7, 8}];

(PARI) A256340(n)=vector(#n=binary(n+1)[2..-1], i, 10^(#n-i))*n~+10^#n\9*7

(MAGMA) [n: n in [1..100000] | Set(Intseq(n)) subset {7, 8}]; // 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), A256341 (digits 8 & 9).

Sequence in context: A248276 A137145 A251626 * A192373 A103680 A219518

Adjacent sequences:  A256337 A256338 A256339 * A256341 A256342 A256343

KEYWORD

nonn,base,easy

AUTHOR

M. F. Hasler, Mar 27 2015

STATUS

approved

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Last modified April 21 22:12 EDT 2019. Contains 322328 sequences. (Running on oeis4.)