A367348 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).

1, 11, 22, 44, 88, 176, 237, 309, 402, 426, 490, 494, 538, 623, 659, 755, 812, 840, 848, 936, 1005, 1056, 1117, 1188, 1269, 1360, 1361, 1372, 1393, 1424, 1465, 1516, 1577, 1648, 1729, 1820, 1821, 1832, 1853, 1884, 1925, 1976, 2037, 2109, 2201, 2213, 2245, 2297, 2369

Offset

1,2

Comments

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

Links

N. J. A. Sloane, Table of n, a(n) for n = 1..20000

Formula

a(837058) = A367347(888508) = 40000026, so a(837058+i) = A367347(888508+i) for i >= 0. - Michael S. Branicky, Nov 17 2023

Mathematica

Join[{1}, NestList[#+First[IntegerDigits[#]]+10Mod[#, 10]&, 11, 100]] (* Paolo Xausa, Nov 17 2023 *)

Prog

(Python)
from itertools import islice
def agen(): # generator of terms
    yield 1
    an = 11
    while True:
        yield an
        s = str(an)
        an += int(s[0]) + 10*int(s[-1])
print(list(islice(agen(), 55))) # Michael S. Branicky, Nov 17 2023

Crossrefs

Cf. A121805, A367347.

Sequence in context: A122613 A115768 A242958 * A005015 A070069 A178664

Adjacent sequences: A367345 A367346 A367347 * A367349 A367350 A367351

Keyword

nonn,base

Author

N. J. A. Sloane, Nov 16 2023

Status

approved