OFFSET
1,2
COMMENTS
More informally: write the terms in decimal under each other, right-justified; the digits on each diagonal in upwards direction sum at most to 9.
See also A298359 for a similar sequence.
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..1380
Rémy Sigrist, PARI program for A298425
Rémy Sigrist, Logarithmic scatterplot of a(n) for n = 1..5000 (with powers of 10 highlighted)
EXAMPLE
The first 25 terms, alongside 10^(25-n) * a(n), are:
n a(n) 10^(25-n) * a(n)
-- ---- -------------------------
1 1 1000000000000000000000000
2 2 200000000000000000000000
3 3 30000000000000000000000
4 4 4000000000000000000000
5 5 500000000000000000000
6 6 60000000000000000000
7 7 7000000000000000000
8 8 800000000000000000
9 9 90000000000000000
10 100 100000000000000000
11 10 1000000000000000
12 11 110000000000000
13 12 12000000000000
14 13 1300000000000
15 14 140000000000
16 15 15000000000
17 16 1600000000
18 17 170000000
19 18 18000000
20 19 1900000
21 1000 10000000
22 20 20000
23 21 2100
24 22 220
25 23 23
The terms on the third column can be summed without carry in decimal base.
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Jan 19 2018
STATUS
approved