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A235202 Numbers written in an alternating binary-then-quaternary base. 1
1, 10, 11, 20, 21, 30, 31, 100, 101, 110, 111, 120, 121, 130, 131, 1000, 1001, 1010, 1011, 1020, 1021, 1030, 1031, 1100, 1101, 1110, 1111, 1120, 1121, 1130, 1131, 2000, 2001, 2010, 2011, 2020, 2021, 2030, 2031, 2100 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Mixed-radix number representation produced by a serial counter with generating sequence (1, 3, 1, 3, ...) = A010684.

Places reading from the right have values (1, 2, 8, 16, 64, 128, ...) = unsigned A094014.

Conjecture: This sequence interpreted as quaternary (base 4) numbers gives A126001 (hence a simplified scheme for computing that sequence).

LINKS

Jeremy Gardiner, Table of n, a(n) for n = 1..1024

EXAMPLE

a(15) = 131 since 15 = 1*1+3*2+1*8.

PROG

(Chipmunk BASIC) # see www.nicholson.com/rhn/basic/

do : rem serial counter

z=z+1

if z>1 then z=0 : y=y+1

if y>3 then y=0 : x=x+1

if x>1 then x=0 : w=w+1

if w>3 then print : end

s$=str$(w)+str$(x)+str$(y)+str$(z)

c=val(s$) : rem strip leading zeros

print str$(c)+", ";

loop

CROSSREFS

Cf. A109827 (Numbers written in an alternating binary-then-ternary base).

Sequence in context: A165265 A197652 A261909 * A049345 A007623 A109827

Adjacent sequences:  A235199 A235200 A235201 * A235203 A235204 A235205

KEYWORD

nonn,base

AUTHOR

Jeremy Gardiner, Jan 04 2014

STATUS

approved

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Last modified February 16 04:34 EST 2019. Contains 320140 sequences. (Running on oeis4.)