A256341 - OEIS

A256341

Numbers which have only digits 8 and 9 in base 10.

8, 9, 88, 89, 98, 99, 888, 889, 898, 899, 988, 989, 998, 999, 8888, 8889, 8898, 8899, 8988, 8989, 8998, 8999, 9888, 9889, 9898, 9899, 9988, 9989, 9998, 9999, 88888, 88889, 88898, 88899, 88988, 88989, 88998, 88999, 89888, 89889

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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) + A002281(A000523(n+1)) = A256341(n) + A256077(n) etc.

MATHEMATICA

Flatten[Table[FromDigits[#, 10]&/@Tuples[{8, 9}, n], {n, 5}]]

PROG

(Magma) [n: n in [1..35000] | Set(IntegerToSequence(n, 10)) subset {8, 9}];

(PARI) A256341(n)=vector(#n=binary(n+1)[2..-1], i, 10^(#n-i))*n~+10^#n\9*8

(Magma) [n: n in [1..100000] | Set(Intseq(n)) subset {8, 9}]; // Vincenzo Librandi, Aug 19 2016

(Python)

def a(n): return int(bin(n+1)[3:].replace('0', '8').replace('1', '9'))

print([a(n) for n in range(1, 45)]) # Michael S. Branicky, Aug 09 2021

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).

Sequence in context: A195991 A304410 A248290 * A116249 A256162 A175556

Adjacent sequences: A256338 A256339 A256340 * A256342 A256343 A256344

KEYWORD

nonn,base,easy

AUTHOR

M. F. Hasler, Mar 27 2015

STATUS

approved