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, 5963015642907, 23548897033949, 156701172827632, 745354652534976, 758666893673274, 7453694087868501, 77198164845775648, 505525028614365003
Offset: 1
Links
- Eric Weisstein's World of Mathematics, Pronic Number
Crossrefs
Extensions
a(14)-a(16) from Lars Blomberg, Jun 10 2011
a(17) added and name edited by Giovanni Resta, Oct 09 2019
a(18)-a(25) from Max Alekseyev, Jul 25 2024