login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A301478 a(n) is the product of the n-th term of A301382 and its initial digit. 1
1, 4, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 25, 36, 40, 42, 44, 46, 48, 49, 50, 52, 54, 56, 58, 64, 81, 90, 93, 96, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The sequence is monotonically increasing, as stated in the Definition section of A301382.

Equivalently, these are the numbers of the form k * A000030(k) for some k > 0. - Rémy Sigrist, Mar 22 2018

LINKS

Jean-Marc Falcoz, Table of n, a(n) for n = 1..10000

EXAMPLE

P is the product a(n) * [the first digit of a(n)] for every term of A301382:

a(1) = 1 is the product P = 1 * 1,

a(2) = 4 is the product P = 2 * 2,

a(3) = 9 is the product P = 3 * 3,

a(4) = 10 is the product P = 10 * 1,

a(5) = 11 is the product P = 11 * 1,

a(6) = 12 is the product P = 12 * 1,

Etc.

PROG

(PARI) p = vector(131, k, oo); for (n=1, #p, x = n*digits(n)[1]; if (x<=#p, p[x] = min(p[x], n))); for (k=1, #p, if (p[k] != oo, print1 (p[k]*digits(p[k])[1] ", "))) \\ Rémy Sigrist, Mar 22 2018

CROSSREFS

Cf. A000030, A301382.

Sequence in context: A171001 A088037 A071768 * A173297 A161913 A020673

Adjacent sequences:  A301475 A301476 A301477 * A301479 A301480 A301481

KEYWORD

nonn,base

AUTHOR

Eric Angelini and Jean-Marc Falcoz, Mar 22 2018

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 26 09:52 EDT 2019. Contains 322472 sequences. (Running on oeis4.)