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A053313 a(n) contains n digits (either '2' or '9') and is divisible by 2^n. 0
2, 92, 992, 2992, 92992, 292992, 2292992, 22292992, 222292992, 2222292992, 22222292992, 922222292992, 9922222292992, 29922222292992, 929922222292992, 9929922222292992, 99929922222292992, 999929922222292992 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..18.

FORMULA

a(n)=a(n-1)+10^(n-1)*(2+7*[a(n-1)/2^(n-1) mod 2]) i.e. a(n) ends with a(n-1); if (n-1)-th term is divisible by 2^n then n-th term begins with a 2, if not then n-th term begins with a 7.

MATHEMATICA

Select[Flatten[Table[FromDigits/@Tuples[{2, 9}, n], {n, 18}]], Divisible[ #, 2^IntegerLength[ #]]&] (* Harvey P. Dale, Feb 07 2015 *)

CROSSREFS

Cf. A023400, A050621, A050622, A035014.

Sequence in context: A116162 A116293 A030985 * A226404 A166825 A042057

Adjacent sequences:  A053310 A053311 A053312 * A053314 A053315 A053316

KEYWORD

base,nonn

AUTHOR

Henry Bottomley, Mar 06 2000

STATUS

approved

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Last modified December 12 09:36 EST 2019. Contains 329953 sequences. (Running on oeis4.)