The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A272896 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A272896

Difference between the number of odd and even digits in the decimal expansion of 2^n.
(history; published version)

#17 by N. J. A. Sloane at Tue Mar 14 20:56:01 EDT 2017

STATUS

proposed

approved

#16 by Indranil Ghosh at Mon Mar 13 10:00:16 EDT 2017

STATUS

editing

proposed

#15 by Indranil Ghosh at Mon Mar 13 09:53:15 EDT 2017

FORMULA

a(n) = A055254(n) - A055253(n) = A196564(2^n) - A196563(2^n). - Indranil Ghosh, Mar 13 2017

CROSSREFS

Cf. A000079, A055253, A055254, A196563, A196564, A272898.

#14 by Indranil Ghosh at Mon Mar 13 09:43:44 EDT 2017

LINKS

Indranil Ghosh, <a href="/A272896/b272896.txt">Table of n, a(n) for n = 0..10000</a>

PROG

(PARI) a(n) = #select(x -> x%2, digits(2^n)) - #select(x -> !(x%2), digits(2^n));

for(n=0, 78, print1(a(n), ", ")) \\ Indranil Ghosh, Mar 13 2017

(Python)

def A272896(n):

....x=y=0

....for i in str(2**n):

........if int(i)%2: x+=1

........else: y+=1

....return x - y # Indranil Ghosh, Mar 13 2017

STATUS

approved

editing

#13 by Wolfdieter Lang at Tue May 24 16:26:40 EDT 2016

STATUS

editing

approved

#12 by Wolfdieter Lang at Tue May 24 16:26:14 EDT 2016

COMMENTS

All vanishing entries are a(A272898(k)) = 0, k >= 1. - Wolfdieter Lang, May 24 2016

CROSSREFS

Cf. A000079, A272898.

STATUS

proposed

editing

#11 by Seiichi Manyama at Sat May 14 23:05:48 EDT 2016

STATUS

editing

proposed

Discussion

Sat May 14

23:07

Seiichi Manyama: @Michel Marcus Thank you. I change the title by your suggestion.

Sun May 15

01:41

Michel Marcus: ok thanks. But I must say that I much prefer sequence A272898

#10 by Seiichi Manyama at Sat May 14 23:05:28 EDT 2016

NAME

Difference between the number of odd and the number of even digits in the decimal digits expansion of 2^n.

STATUS

proposed

editing

#9 by Michel Marcus at Sat May 14 13:40:29 EDT 2016

STATUS

editing

proposed

#8 by Michel Marcus at Sat May 14 13:39:09 EDT 2016

DATA

1, -1, -1, -1, 0, 0, -2, -1, -1, 1, -2, -4, -2, 0, -1, -1, 1, 2, -4, -4, -1, 1, -1, -5, 2, 2, -4, 1, -3, 1, 0, -4, -2, 2, 3, 3, 1, 4, -2, 2, 5, 3, -1, -5, -2, -2, -2, 1, -1, 3, -4, 0, 2, 2, -1, -1, 5, 2, 2, -4, -3, 1, -5, -1, 0, 0, -6, 3, 5, 5, 2, -10, -8, 2, -3, 7, 9, 0, 0, -4, -1, 1, -5, 3, 2, -2, 6, -1, -5, -1, -4, -8, 6, 6, -7, 7, 5, -4, 6, -4, -9

STATUS

proposed

editing

Discussion

Sat May 14

13:40

Michel Marcus: Data section reduced : there were more than 350 characters. Should be around 260.

13:40

Michel Marcus: Name suggestion : Difference between the number of odd and even digits in the decimal expansion of 2^n.