A367612 Numbers that are the comma-child of exactly one positive number.

11, 12, 22, 23, 24, 33, 34, 35, 36, 44, 45, 46, 47, 48, 55, 56, 57, 58, 59, 60, 61, 66, 67, 68, 69, 70, 71, 72, 73, 77, 78, 79, 80, 81, 82, 83, 84, 85, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122

Offset

1,1

Comments

This is the complement of A367611.

See A367338 for definition of comma-child.

May also be called numbers that have a positive comma-predecessor.

Links

Table of n, a(n) for n=1..72.

Eric Angelini, Michael S. Branicky, Giovanni Resta, N. J. A. Sloane, and David W. Wilson, The Comma Sequence: A Simple Sequence With Bizarre Properties, arXiv:2401.14346, Fibonacci Quarterly 62:3 (2024), 215-232.

Eric Angelini, Michael S. Branicky, Giovanni Resta, N. J. A. Sloane, and David W. Wilson, The Comma Sequence: A Simple Sequence With Bizarre Properties, Local copy.

N. J. A. Sloane, Eric Angelini's Comma Sequence, Experimental Math Seminar, Rutgers Univ., January 18, 2024, Youtube video; Slides

Prog

(Python)
def ok(n): y = int(str(n)[0]); x = (n-y)%10; return n - y - 10*x > 0
print([k for k in range(1, 123) if ok(k)]) # Michael S. Branicky, Dec 15 2023

Crossrefs

Cf. A121805, A367611.

Sequence in context: A231871 A192287 A084855 * A367340 A101233 A118512

Adjacent sequences: A367609 A367610 A367611 * A367613 A367614 A367615

Keyword

nonn,base

Author

Michael S. Branicky and N. J. A. Sloane, Dec 15 2023

Status

approved