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A124210 a(n) is the number of positive integers k such that sum of digits of 2^k equals n. 0
0, 1, 0, 1, 1, 0, 2, 2, 0, 1, 1, 0, 1, 2, 0, 0, 0, 0, 2, 1, 0, 1, 0, 0, 2, 2, 0, 0, 2, 0, 1, 0, 0, 0, 1, 0, 2, 0, 0, 1, 2, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 2, 0, 2, 1, 0, 2, 2, 0, 1, 1, 0, 1, 1, 0, 3, 1, 0, 1, 1, 0, 1, 2, 0, 1, 2, 0, 2, 0, 0, 2, 2, 0, 1, 2, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

Table of n, a(n) for n=1..100.

EXAMPLE

a(7) = 2 because 2^4 = 16 and 2^10 = 1024 and the sums of the digits of these two numbers are 7; and there are no other numbers like this.

MATHEMATICA

Table[Length[Select[Range[1000], Plus @@ IntegerDigits[2^# ] == n &]], {n, 100}]

CROSSREFS

Sequence in context: A219946 A117449 A004594 * A110568 A088689 A076898

Adjacent sequences:  A124207 A124208 A124209 * A124211 A124212 A124213

KEYWORD

base,nonn

AUTHOR

Tanya Khovanova, Dec 13 2006

STATUS

approved

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Last modified March 29 13:04 EDT 2017. Contains 284270 sequences.