A167179 - OEIS

A167179

The number of additional armies one receives in Parker Brothers' (now part of Hasbro) game of Risk for turning in the n-th set of three different or alike cards.

4, 6, 8, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Although this sequence is theoretically infinite, in actual practice, terms greater than a(15) are rarely reached.

LINKS

Table of n, a(n) for n=1..58.

Hasbro, Rules of Risk

Wikipedia, Risk game

Index entries for linear recurrences with constant coefficients, signature (2,-1).

FORMULA

a(n) = 2*(n+1) for n<=5, otherwise a(n) = 5*(n-3).