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A281552 Write n in the Elias gamma code and sum the positions where there is a '1' followed immediately to the right by a '0', counting the leftmost digit as position 1. 1
0, 1, 1, 2, 2, 6, 2, 3, 3, 9, 3, 8, 8, 9, 3, 4, 4, 12, 4, 11, 11, 12, 4, 10, 10, 18, 10, 11, 11, 12, 4, 5, 5, 15, 5, 14, 14, 15, 5, 13, 13, 23, 13, 14, 14, 15, 5, 12, 12, 22, 12, 21, 21, 22, 12, 13, 13, 23, 13, 14, 14, 15, 5, 6, 6, 18, 6, 17, 17, 18, 6, 16, 16, 28, 16, 17, 17, 18, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Indranil Ghosh, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A049501(A171885(n)) for n > = 1.

EXAMPLE

For n = 6 , the Elias gamma code for n is '11010'. In '11010', the positions of '1' followed immediately to the right by '0' counting from left are 2 and 4. So, a(6) = 2 + 4 = 6.

For n = 10, the Elias gamma code for n is '1110010'. In '1110010', the positions of '1' followed immediately to the right by '0' counting from left are 3 and 6. So, a(10) = 3 + 6 = 9.

PROG

(Python)

def a(n):

....x= A281149(n)

....s=0

....for i in range(1, len(x)):

........if x[i-1]=="1" and x[i]=="0":

............s+=i

....return s

CROSSREFS

Cf. A049501, A171885, A281149, A281388, A281497.

Sequence in context: A278250 A134339 A162299 * A205506 A110141 A293443

Adjacent sequences:  A281549 A281550 A281551 * A281553 A281554 A281555

KEYWORD

nonn,base

AUTHOR

Indranil Ghosh, Jan 24 2017

STATUS

approved

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Last modified March 20 20:14 EDT 2019. Contains 321352 sequences. (Running on oeis4.)