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Sum of first and last digits of n. Different from A115299.
9

%I #10 Apr 24 2024 13:00:11

%S 0,2,4,6,8,10,12,14,16,18,1,2,3,4,5,6,7,8,9,10,2,3,4,5,6,7,8,9,10,11,

%T 3,4,5,6,7,8,9,10,11,12,4,5,6,7,8,9,10,11,12,13,5,6,7,8,9,10,11,12,13,

%U 14,6,7,8,9,10,11,12,13,14,15,7,8,9,10,11,12,13,14,15,16,8,9,10,11,12,13,14

%N Sum of first and last digits of n. Different from A115299.

%F a(n) = A000030(n) + A010879(n). - _M. F. Hasler_, Apr 22 2024

%t Total[{First[IntegerDigits[#]],Last[IntegerDigits[#]]}]&/@Range[90] (* _Harvey P. Dale_, Aug 21 2018 *)

%o (PARI) apply( {A088133(n)=n\10^logint(n+!n, 10)+n%10}, [0..99]) \\ _M. F. Hasler_, Apr 22 2024

%o (Python) list(map(A088133 := lambda n: int(str(n)[0])+n%10, range(99))) # _M. F. Hasler_, Apr 22 2024

%Y Cf. A000030 (first digit of n), A010879 (last digit of n).

%Y Cf. A046704, A007953, A088134, A088135, A088136.

%K easy,nonn,base

%O 0,2

%A _Zak Seidov_, Sep 20 2003

%E Extended to a(0) = 0 by _M. F. Hasler_, Apr 22 2024