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A048529 a(n) is the smallest value of m such that A002378(m), the m-th oblong number, contains exactly n 0's. 10
0, 24, 100, 624, 1000, 10001, 10000, 100001, 100000, 1000001, 1000000, 10000001, 10000000, 100000001, 100000000, 1000000001, 1000000000, 10000000001, 10000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..19.

Eric Weisstein's World of Mathematics, Pronic Number

EXAMPLE

From Jesse Sealand, Oct 05 2019: (Start)

a(1) = 0 since A002378(0) = 0;

a(2) = 24 since A002378(24) = 600;

a(3) = 100 since A002378(100) = 10100;

a(4) = 624 since A002378(624) = 390000, etc.

(End).

MATHEMATICA

a[n_] := Block[{a = 0}, While[Count[IntegerDigits[a*(a + 1)], 0] != n, ++a]; Return[a]]; a /@ Range[1, 10] (* Julien Kluge, Dec 15 2016 *)

CROSSREFS

Cf. A002378, A048530.

Cf. A048531, A048533, A048535, A048537, A048539, A048541, A048543, A048545, A048547.

Sequence in context: A100152 A233405 A297798 * A213842 A333033 A269047

Adjacent sequences:  A048526 A048527 A048528 * A048530 A048531 A048532

KEYWORD

nonn,base,more

AUTHOR

Patrick De Geest, May 15 1999

EXTENSIONS

a(16)-a(19) from Lars Blomberg, Jun 10 2011

Name edited by Jesse Sealand, Oct 05 2019

STATUS

approved

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Last modified October 28 07:30 EDT 2021. Contains 348320 sequences. (Running on oeis4.)