A048531 a(n) is the smallest value of m such that A002378(m), the m-th oblong number, contains exactly n 1's.

3, 10, 105, 1010, 10203, 33928, 105551, 335128, 1054130, 12313046, 100573943, 333192303, 1054092885, 4261585525, 30184681729, 133083117303, 331829837885

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Eric Weisstein's World of Mathematics, Pronic Number

Example

From Jesse Sealand, Oct 06 2019: (Start)
a(1) = 3 since A002378(3) = 12;
a(2) = 10 since A002378(10) = 110;
a(3) = 105 since A002378(105) = 11130;
a(4) = 1010 since A002378(1010) = 1021110, etc.
(End).

Crossrefs

Cf. A048532, A002378.

Cf. A048529, A048533, A048535, A048537, A048539, A048541, A048543, A048545, A048547.

Sequence in context: A117664 A091342 A093454 * A073306 A290557 A034945

Adjacent sequences: A048528 A048529 A048530 * A048532 A048533 A048534

Keyword

nonn,base,more

Author

Patrick De Geest, May 15 1999

Extensions

a(13)-a(16) from Lars Blomberg, Jun 10 2011

Name edited by Jesse Sealand, Oct 06 2019

a(17) from Giovanni Resta, Oct 09 2019

Status

approved