A367611 Numbers that are not the comma-child of any positive number.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, 14, 15, 16, 17, 18, 19, 20, 21, 25, 26, 27, 28, 29, 30, 31, 32, 37, 38, 39, 40, 41, 42, 43, 49, 50, 51, 52, 53, 54, 62, 63, 64, 65, 74, 75, 76, 86, 87, 98

Offset

1,2

Comments

A subsequence of A367600.

This 50-term sequence was found by David W. Wilson in 2007. See the Eric Angelini link.

See A367338 for definition of comma-child.

Links

Table of n, a(n) for n=1..50.

Eric Angelini, The Commas Sequence, Message to Sequence Fans, Sep 06 2016. [Cached copy, with permission]

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 < 1
print([k for k in range(1, 99) if ok(k)]) # Michael S. Branicky, Dec 15 2023

Crossrefs

Cf. A121805, A367600.

A367612 gives the complement.

Sequence in context: A302028 A367600 A023779 * A247812 A050724 A336813

Adjacent sequences: A367608 A367609 A367610 * A367612 A367613 A367614

Keyword

nonn,base,fini,full,changed

Author

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

Status

approved