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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 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 * A287447 A110568 A088689 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 December 16 01:14 EST 2018. Contains 318158 sequences. (Running on oeis4.)