A048533 a(n) is the smallest value of m such that A002378(m), the m-th oblong number, contains exactly n 2's.

1, 16, 141, 458, 1458, 10593, 36458, 471933, 471404, 3496458, 14930593, 149072541, 471446966, 149071198, 14907133333, 114989226548, 471404524016, 1510636363333, 14360440530228, 47140441472504, 149071332733333, 1490343155861166, 4712983368549333, 24955404665166666, 149070527690846966

Offset

1,2

Links

Table of n, a(n) for n=1..25.

Eric Weisstein's World of Mathematics, Pronic Number

Example

From Jesse Sealand, Oct 06 2019: (Start)
a(1) = 1 since A002378(1) = 2;
a(2) = 16 since A002378(16) = 272;
a(3) = 141 since A002378(141) = 20022;
a(4) = 458 since A002378(458) = 210222, etc.
(End).

Crossrefs

Cf. A048534, A002378.

Cf. A048529, A048531, A048535, A048537, A048539, A048541, A048543, A048545, A048547.

Sequence in context: A300878 A301488 A232311 * A303145 A213349 A336239

Adjacent sequences: A048530 A048531 A048532 * A048534 A048535 A048536

Keyword

nonn,base

Author

Patrick De Geest, May 15 1999

Extensions

a(15)-a(16) from Lars Blomberg, Jun 10 2011

Name edited by Jesse Sealand, Oct 06 2019

a(17) from Giovanni Resta, Oct 09 2019

a(18)-a(25) from Max Alekseyev, Jul 25 2024

Status

approved