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A069025 Smallest power of 2 with digital sum (A007953) n, or 0 if no such number exists. 1
1, 2, 0, 4, 32, 0, 16, 8, 0, 64, 128, 0, 256, 2048, 0, 0, 0, 0, 4096, 8192, 0, 16384, 0, 0, 65536, 32768, 0, 0, 524288, 0, 1048576, 0, 0, 0, 134217728, 0, 16777216, 0, 0, 67108864, 8388608, 0, 268435456, 0, 0, 4398046511104, 2147483648, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(3k)=0. In general about half the entries are nonzero.

LINKS

Table of n, a(n) for n=1..49.

EXAMPLE

Both 2^4=16 and 2^10=1024 have a digital sum of 7 but 2^4 is the smaller so it is the one presented.

MATHEMATICA

a = Table[0, {50}]; Do[b = Plus @@ IntegerDigits[2^n]; If[b < 51 && a[[b]] == 0, a[[b]] = 2^n], {n, 0, 10^4}]; a

CROSSREFS

Cf. A007632.

Sequence in context: A199852 A055978 A245695 * A145962 A066442 A171388

Adjacent sequences:  A069022 A069023 A069024 * A069026 A069027 A069028

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, Apr 02 2002

EXTENSIONS

Edited by Robert G. Wilson v, Nov 05 2002

STATUS

approved

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Last modified October 20 07:17 EDT 2018. Contains 316378 sequences. (Running on oeis4.)