A099102 Natural numbers n with fewer digits than sigma(n).

6, 8, 9, 48, 54, 56, 60, 63, 64, 66, 68, 70, 72, 74, 75, 76, 78, 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 360, 384, 390, 396, 408, 420, 432, 440, 444, 448, 450, 456, 460, 462, 468, 476, 480, 486, 490, 492, 498, 500, 504, 510, 512, 516, 520

Offset

1,1

Comments

This sequence is a comment on the referenced comment of R. K. Guy concerning the occurrence of 301-digit numbers.

Links

Table of n, a(n) for n=1..61.

R. K. Guy, Re: Odd Perfect Numbers, Sep 23 2004 post to NMBRTHRY mailing list.

Example

6 is in the sequence because 1, the number of digits in 6, is less than 2, the number of digits in 12 = sigma(6).

Prog

(PARI) isok(n) = length(digits(n, 10)) < length(digits(sigma(n), 10)) \\ Michel Marcus, Jul 23 2013

Crossrefs

Cf. A000203, A099103.

Sequence in context: A174213 A284990 A238621 * A001743 A366728 A256964

Adjacent sequences: A099099 A099100 A099101 * A099103 A099104 A099105

Keyword

base,easy,nonn

Author

Walter Nissen, Sep 25 2004

Status

approved