

A301478


a(n) is the product of the nth 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

JeanMarc 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 JeanMarc Falcoz, Mar 22 2018


STATUS

approved



