A117771 Numbers n such that digit sum of 2^n is less than or equal to n.

5, 9, 10, 17, 70

Offset

1,1

Comments

Probably there are no more terms.

Probably 5 and 70 are the only cases when digit sum of 2^n is equal to n. - Tanya Khovanova, Jul 23 2006

Probably 1, 2, 5 and 70 are the only cases when digit sum of 2^n is divisible by n. - Zak Seidov, Jul 24 2006

Links

Table of n, a(n) for n=1..5.

Mathematica

Select[Range[80], #>=Total[IntegerDigits[2^#]]&] (* Harvey P. Dale, Sep 22 2019 *)

Prog

(PARI) isok(n) = d = digits(2^n); sum(i=1, #d, d[i]) <= n; \\ Michel Marcus, Aug 17 2013

Crossrefs

Cf. A001370.

Sequence in context: A136318 A242139 A216765 * A227853 A275240 A175437

Adjacent sequences: A117768 A117769 A117770 * A117772 A117773 A117774

Keyword

nonn,base,fini

Author

Joshua Zucker, Jul 24 2006

Status

approved