login
A084926
Inverse hyperbolic cotangent reducible numbers. The hyperbolic analog of the non-Stormer numbers (A002312).
1
5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 26, 27, 29, 31, 33, 34, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 56, 57, 59, 61, 63, 64, 65, 67, 69, 71, 73, 75, 76, 77, 79, 81, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 116, 117, 118
OFFSET
1,1
COMMENTS
n is in the sequence if y=(xn+1)/(x+n) is an integer for some integer x where 1<x<n.
PROG
(PARI) for(n=1, 120, x=1; b=0; while(x<n, x=x+1; r=(x+n)*floor((x*n+1)/(x+n)); if(r>=(x*n+1), b=b+1)); if(b>0, print1(n, ", ")))
CROSSREFS
Cf. A002312 (non-Stormer numbers), A084925 (arccoth irreducible).
Sequence in context: A342378 A099047 A174392 * A333038 A049013 A267872
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jun 12 2003
STATUS
approved