A061515 a(0) = 1; a(n) is obtained by incrementing each digit of a(n-1) by 3.

1, 4, 7, 10, 43, 76, 109, 4312, 7645, 10978, 43121011, 76454344, 109787677, 431210111091010, 7645434443124343, 10978767776457676, 43121011109101010978109109, 76454344431243434312101143124312, 109787677764576767645434476457645, 431210111091010109781091091097876771097810978

Offset: 0

Author

Amarnath Murthy, May 08 2001

Keywords

• base
• nonn

Comments

In A061511-A061522, A061746-A061750 when the incremented digit exceeds 9 it is written as a 2-digit string. So 9+1 becomes the 2-digit string 10, etc.

Programs

Python

from itertools import accumulate, repeat
def f(n, _): return int("".join(str(int(d)+3) for d in str(n)))
def aupton(nn): return list(accumulate(repeat(1, nn+1), f))
print(aupton(19)) # Michael S. Branicky, Mar 19 2022

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), May 11 2001

a(17) corrected and a(18), a(19) by Georg Fischer, Mar 19 2022