A048539 a(n) is the smallest value of m such that A002378(m), the m-th oblong number, contains exactly n 5's.

7, 23, 74, 2248, 2292, 23506, 50552, 742667, 2357022, 22706949, 74555050, 703955648, 745020507, 3996943276, 74333434976, 244040827632, 505525029504

Offset

1,1

Links

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

Eric Weisstein's World of Mathematics, Pronic Number

Crossrefs

Cf. A048540, A002378.

Cf. A048529, A048531, A048533, A048535, A048537, A048541, A048543, A048545, A048547.

Sequence in context: A034563 A242496 A356684 * A240526 A018886 A145842

Adjacent sequences: A048536 A048537 A048538 * A048540 A048541 A048542

Keyword

nonn,base,more

Author

Patrick De Geest, May 15 1999

Extensions

a(14)-a(16) from Lars Blomberg, Jun 10 2011

a(17) added and name edited by Giovanni Resta, Oct 09 2019

Status

approved