A367358 - OEIS

%I #12 Nov 22 2023 08:16:36

%S 1,2,3,4,5,7,8,11,13,17,19,21,22,24,45,69,90,107,127,145,164,185,204,

%T 422,614,822,1007,1174,1392,1585,1757,1943,4115,6039,8123,9974,11641,

%U 13814,15738,17822,19673,41413,60643,81477,99995,114281,132138,151369,172201,190720,408111,646206,854539,1039724,1373058,1551630,1743937,1952271

%N Indices k at which either the leading digit or the length of A121805(k) changes.

%o (Python)

%o def agen(): # generator of terms

%o     n, an, y, prev_lead, prev_length = 1, 1, 1, None, None

%o     while y < 10:

%o         san = str(an)

%o         lead, length = san[0], len(san)

%o         if lead != prev_lead or length != prev_length:

%o             yield n

%o         an, y = an + 10*(an%10), 1

%o         while y < 10:

%o             if str(an+y)[0] == str(y):

%o                 an += y

%o                 break

%o             y += 1

%o         n, prev_lead, prev_length = n+1, lead, length

%o print(list(agen())) # _Michael S. Branicky_, Nov 22 2023

%Y Cf. A121805, A366487, A367359.

%K nonn,base,fini,full

%O 1,2

%A _N. J. A. Sloane_, Nov 21 2023

%E More terms from _Michael S. Branicky_, Nov 22 2023