A218450 Number of digits of n plus number of digits of n equal to 1, 2, 4, or 8.

2, 2, 1, 2, 1, 1, 1, 2, 1, 3, 4, 4, 3, 4, 3, 3, 3, 4, 3, 3, 4, 4, 3, 4, 3, 3, 3, 4, 3, 2, 3, 3, 2, 3, 2, 2, 2, 3, 2, 3, 4, 4, 3, 4, 3, 3, 3, 4, 3, 2, 3, 3, 2, 3, 2, 2, 2, 3, 2, 2, 3, 3, 2, 3, 2, 2, 2, 3, 2, 2, 3, 3, 2, 3, 2, 2, 2, 3, 2, 3, 4, 4, 3, 4, 3, 3, 3

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

Sequence in context: A297382 A258257 A086600 * A025912 A029441 A342263

Adjacent sequences: A218447 A218448 A218449 * A218451 A218452 A218453

Keyword

nonn,easy,base

Author

David Williams, Oct 28 2012

Status

approved