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A117079 a(1) = 1; a(n) = 2*a(n-1) + (number of digits in a(n-1)). 1
1, 3, 7, 15, 32, 66, 134, 271, 545, 1093, 2190, 4384, 8772, 17548, 35101, 70207, 140419, 280844, 561694, 1123394, 2246795, 4493597, 8987201, 17974409, 35948826, 71897660, 143795328, 287590665, 575181339, 1150362687, 2300725384 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

1*2+1=3

3*2+1=7

7*2+1=15

15*2+2=3

etc.

MATHEMATICA

a[1] = 1; a[n_] := a[n] = 2a[n - 1] + Floor[Log[10, a[n - 1]]] + 1 - Robert G. Wilson v, Apr 20 2006

RecurrenceTable[{a[1]==1, a[n]==2a[n-1]+IntegerLength[a[n-1]]}, a[n], {n, 40}] (* Harvey P. Dale, May 03 2011 *)

NestList[2#+IntegerLength[#]&, 1, 30] (* Harvey P. Dale, Oct 01 2012 *)

CROSSREFS

Sequence in context: A147250 A066175 A132978 * A026745 A139333 A099444

Adjacent sequences:  A117076 A117077 A117078 * A117080 A117081 A117082

KEYWORD

easy,nonn,base

AUTHOR

Zededarian Zee (Zededarian(AT)Gmail.com), Apr 19 2006

EXTENSIONS

More terms from Stefan Steinerberger, Jonathan Vos Post, Robert G. Wilson v and James Greene (jmg482(AT)psu.edu), Apr 20 2006. Also from Atilla Bora (borabanana(AT)gmail.com), Apr 23 2006

STATUS

approved

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Last modified May 26 04:46 EDT 2019. Contains 323579 sequences. (Running on oeis4.)