A337843 - OEIS

%I #14 Sep 08 2022 08:46:25

%S 1,2,3,4,5,6,7,8,9,10,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,

%T 28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,

%U 51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69

%N a(n) is n + the number of digits in the decimal expansion of n.

%C a(n) is an increasing injective sequence that is not surjective.

%C a(n) is also the sequence of numbers m that can be written as (m + number of digits of m) for some m >= 0, complement of numbers from A081552(n) for n > 1.

%C Sequence is not the same as A101947, first different term is a(77) = 79.

%F a(n) = n + A055642(n).

%e a(10) = 10 + 2 = 12.

%t a[0] = 1; a[n_] := n + IntegerLength[n]; Array[a, 100, 0] (* _Amiram Eldar_, Sep 25 2020 *)

%o (Magma) [1] cat [n + #Intseq(n): n in [1..100]]

%o (PARI) a(n) = if (n==0, 1, n + #digits(n)); \\ _Michel Marcus_, Sep 26 2020

%Y Cf. A055642, A062028, A081552, A230099.

%Y Cf. A110803 (n * the number of digits in the decimal expansion of n).

%K nonn,base

%O 0,2

%A _Jaroslav Krizek_, Sep 25 2020