OFFSET
1,3
COMMENTS
Replace "5" with "x" and extend the definition of a to positive rationals and a becomes an isomorphism between positive rationals under multiplication and polynomials over Z under addition. This remark generalizes A001222, A048675 and A054841: evaluate said polynomial at x=1, x=2 and x=10, respectively.
REFERENCES
Joseph J. Rotman, The Theory of Groups: An Introduction, 2nd ed. Boston: Allyn and Bacon, Inc. 1973. Page 9, problem 1.26.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..1001
Sam Alexander, Post to sci.math.
PROG
(PARI) A090882(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*5^(primepi(f[k, 1])-1)); }; \\ Antti Karttunen, Apr 28 2022
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Sam Alexander, Dec 12 2003
EXTENSIONS
More terms from Ray Chandler, Dec 20 2003
STATUS
approved