A067066 Number of Gnutella users reachable with given connections and hops.

1, 2, 1, 3, 4, 1, 4, 9, 6, 1, 5, 16, 21, 8, 1, 6, 25, 52, 45, 10, 1, 7, 36, 105, 160, 93, 12, 1, 8, 49, 186, 425, 484, 189, 14, 1, 9, 64, 301, 936, 1705, 1456, 381, 16, 1, 10, 81, 456, 1813, 4686, 6825, 4372, 765, 18, 1, 11, 100, 657, 3200, 10885, 23436, 27305, 13120, 1533, 20, 1

Offset: 1

Author

Michael Somos, Feb 17 2002

Keywords

• nonn
• tabl
• easy

Examples

			     1      1      1      1      1      1      1 ...
     2      4      6      8     10     12     14 ...
     3      9     21     45     93    189    381 ...
     4     16     52    160    484   1456   4372 ...
     5     25    105    425   1705   6825  27305 ...
     6     36    186    936   4686  23436 117186 ...
     7     49    301   1813  10885  65317 391909 ...
		

Links

• Jordan Ritter, Why Gnutella Can't Scale. No, Really.

Crossrefs

Cf. A104881.

Formula

T(n,k) = n * Sum_{i=0..k-1} (n-1)^i.

Extensions

Offset corrected, R. J. Mathar, May 22 2016