A067115 - OEIS

A067115

Let N = 1357911131517192123252729... = concatenation of odd numbers. Then a(n) = sum of first n digits of N.

1, 4, 9, 16, 25, 26, 27, 28, 31, 32, 37, 38, 45, 46, 55, 57, 58, 60, 63, 65, 70, 72, 79, 81, 90, 93, 94, 97, 100, 103, 108

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

EXAMPLE

a(6)= 1+3+5+7+9+1 = 26.

MATHEMATICA

Module[{nn=20, codd}, codd=Flatten[IntegerDigits/@(2Range[0, nn]+1)]; Accumulate[ codd]] (* Harvey P. Dale, Jul 09 2021 *)

CROSSREFS

KEYWORD

easy,nonn,base

AUTHOR

STATUS

approved