OFFSET
1,1
COMMENTS
A "digit-position" (DP in short) is the rank of a digit in the succession of the digits of the sequence. At DP#1 we find the digit "2" here. At DP#8 we find"1" (the 1 of 16), etc.
A term > 4 uses more than one digit when it is doubled (2*8 = 16 uses two digits, for instance, 2*50 = 100 uses three digits, etc.) The convention here says that the double of a(n) is visible in the sequence at DP#n. This means that the said double will use sometimes contiguous digits that belong to an existing term, or will use successive digits belonging to two (or more) contiguous terms. The first such example here is a(17) = 56 with 56 "saying" that at DP#56 starts 112 (112 is the double of 56); indeed, DP#56 = 1, DP#57 = 1 and DP#58 = 2 and those three digits are used by a(30) = 91 and a(31) = 121 like this: 9(1, 12)1.
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Eric Angelini and Carole Dubois, Jun 28 2021
STATUS
approved