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A139284
Analog of A121805, but starting with 2.
15
2, 24, 71, 89, 180, 181, 192, 214, 256, 319, 413, 447, 522, 547, 623, 659, 756, 824, 872, 901, 920, 929, 1020, 1021, 1032, 1053, 1084, 1125, 1176, 1237, 1308, 1389, 1480, 1481, 1492, 1513, 1544, 1585, 1636, 1697, 1768, 1849, 1940, 1941, 1952, 1973, 2005
OFFSET
1,1
COMMENTS
It appears that this sequence and A121805 have no terms in common. Furthermore, this sequence exists for at least 1551000000 terms. - Jacques ALARDET, Jul 22 2008
The last term of the sequence is a(194697747222394) = 9999999999999918. - Giovanni Resta, Nov 30 2019
REFERENCES
E. Angelini, "Jeux de suites", in Dossier Pour La Science, pp. 32-35, Volume 59 (Jeux math'), April/June 2008, Paris.
LINKS
Carlos Rivera, Puzzle 980. The "Commas" sequence, The Prime Puzzles and Problems Connection.
MAPLE
a:= proc(n) option remember; local k, t, y; if n=1 then 2 else k:= a(n-1); for y from 0 to 9 do t:= k +10* irem (k, 10) +y; if convert (t, base, 10)[ -1]=y then return t fi od; NULL fi end: seq(a(n), n=1..80); # Alois P. Heinz, Aug 13 2009
MATHEMATICA
a[1] = 2; a[n_] := a[n] = For[x=Mod[a[n-1], 10]; y=0, y <= 9, y++, an = a[n-1] + 10*x + y; If[y == IntegerDigits[an][[1]], Return[an]]]; Array[a, 80] (* Jean-François Alcover, Nov 25 2014 *)
PROG
(Python)
from itertools import islice
def agen(): # generator of terms
an, y = 2, 1
while y < 10:
yield an
an, y = an + 10*(an%10), 1
while y < 10:
if str(an+y)[0] == str(y):
an += y
break
y += 1
print(list(islice(agen(), 47))) # Michael S. Branicky, Apr 08 2022
CROSSREFS
Comma sequences in base 10, starting with 1, 2, 4, 5, 6, 7, 8, 9, 10 are A121805, A139284, A366492, A367337, A367350, A367351, A367352, A367353, A367354. Starting with 3 is trivial, and those starting with 11, 12, 13 are essentially duplicates.
Sequence in context: A100918 A152965 A345692 * A003614 A195189 A119060
KEYWORD
nonn,base,fini
AUTHOR
N. J. A. Sloane (based on Angelini's article), Jun 08 2008
EXTENSIONS
More terms from Alois P. Heinz, Aug 13 2009
STATUS
approved