OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
lim inf a(n)/log_10 n = 1; lim sup a(n)/log_10 n = 2.
MAPLE
f:= proc(n) local L;
L:= convert(n, base, 10);
nops(L) + numboccur(L, {1, 2, 4, 8})
end proc:
map(f, [$1..100]); # Robert Israel, Apr 29 2021
MATHEMATICA
Table[d = IntegerDigits[n]; Length[d] + Count[d, 1] + Count[d, 2] + Count[d, 4] + Count[d, 8], {n, 100}] (* T. D. Noe, Nov 16 2012 *)
Table[IntegerLength[n]+Total[DigitCount[n, 10, {1, 2, 4, 8}]], {n, 100}] (* Harvey P. Dale, Aug 03 2021 *)
PROG
(PARI) a(n) = my(d = digits(n)); #d + #select(x->((x==1) || (x==2) || (x==4) || (x==8)), d); \\ Michel Marcus, Jan 31 2016
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
David Williams, Oct 28 2012
STATUS
approved