

A165722


Positive integers k such that the sum of decimal digits of (16^k  1) equals 6*k.


2



1, 2, 3, 4, 5, 6, 7, 10, 12, 13, 14, 17, 18, 23, 37, 43, 46, 60, 119, 183, 223
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OFFSET

1,2


COMMENTS

Integers k such that A007953(16^k  1) = A008588(k).  Iain Fox, Nov 22 2017
Conjecture: For k > 223, digsum(16^k  1) < 6*k. This would mean that no further terms exist in the sequence.  Iain Fox, Nov 22 2017
No other terms below 10^6.  Iain Fox, Nov 25 2017
For all a(n), 2*a(n) is in A294652.  Iain Fox, Dec 02 2017


LINKS

Table of n, a(n) for n=1..21.


EXAMPLE

For k=1, 161 is 15 with sum of digits 6, so 1 is a term.
For k=2, 16^21 is 255 with sum of digits 12, so 2 is a term.


MATHEMATICA

Select[Range[250], 6#==Total[IntegerDigits[16^#1]]&] (* Harvey P. Dale, Nov 13 2012 *)


PROG

(PARI) is(n) = 6*n == sumdigits(16^n1) \\ Iain Fox, Nov 24 2017


CROSSREFS

Cf. A007953, A294652.
Sequence in context: A165805 A319975 A307625 * A082400 A072993 A018444
Adjacent sequences: A165719 A165720 A165721 * A165723 A165724 A165725


KEYWORD

base,more,nonn


AUTHOR

Max Alekseyev, Sep 24 2009


STATUS

approved



