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A218450 Number of digits of n plus number of digits of n equal to 1, 2, 4, or 8. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified December 1 22:12 EST 2021. Contains 349435 sequences. (Running on oeis4.)