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a(1) = 1, a(2) = 11; thereafter, a(n+1) = a(n) + x + 10*y, where x and y are respectively the first and last digits of a(n).
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%I #27 Nov 17 2023 07:33:35

%S 1,11,22,44,88,176,237,309,402,426,490,494,538,623,659,755,812,840,

%T 848,936,1005,1056,1117,1188,1269,1360,1361,1372,1393,1424,1465,1516,

%U 1577,1648,1729,1820,1821,1832,1853,1884,1925,1976,2037,2109,2201,2213,2245,2297,2369

%N a(1) = 1, a(2) = 11; thereafter, a(n+1) = a(n) + x + 10*y, where x and y are respectively the first and last digits of a(n).

%C This sequence and A367347 are simple models for the Commas sequence A121805.

%H N. J. A. Sloane, <a href="/A367348/b367348.txt">Table of n, a(n) for n = 1..20000</a>

%F a(837058) = A367347(888508) = 40000026, so a(837058+i) = A367347(888508+i) for i >= 0. - _Michael S. Branicky_, Nov 17 2023

%t Join[{1},NestList[#+First[IntegerDigits[#]]+10Mod[#,10]&,11,100]] (* _Paolo Xausa_, Nov 17 2023 *)

%o (Python)

%o from itertools import islice

%o def agen(): # generator of terms

%o yield 1

%o an = 11

%o while True:

%o yield an

%o s = str(an)

%o an += int(s[0]) + 10*int(s[-1])

%o print(list(islice(agen(), 55))) # _Michael S. Branicky_, Nov 17 2023

%Y Cf. A121805, A367347.

%K nonn,base

%O 1,2

%A _N. J. A. Sloane_, Nov 16 2023