A124210 - OEIS

A124210

a(n) is the number of positive integers k such that sum of digits of 2^k equals n.

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 * A287447 A110568 A088689

Adjacent sequences: A124207 A124208 A124209 * A124211 A124212 A124213

KEYWORD

base,nonn

AUTHOR

Tanya Khovanova, Dec 13 2006

STATUS

approved