A058973 First integer reached in A058972.

1, 2, 3, 2, 4, 2, 5, 9, 2, 4, 8, 8, 9, 9, 10, 8, 8, 11, 2, 2, 12, 2, 13, 13, 14, 15, 4, 16, 2, 17, 4, 35, 19, 8, 23, 9, 8, 22, 25, 2, 26, 25, 2, 2, 24, 28, 8, 10, 4, 29, 2, 26, 29, 2, 2, 35, 33, 6, 2, 38, 33, 33, 40, 2, 68, 4, 8, 44, 41, 8, 4, 46, 35, 43, 49, 50, 2, 42, 8, 40, 58, 4, 59, 43, 61

Offset

1,2

Links

Table of n, a(n) for n=1..85.

P. Schogt, The Wild Number Problem: math or fiction?, arXiv preprint arXiv:1211.6583 [math.HO], 2012. - From N. J. A. Sloane, Jan 03 2013

Example

A058972(1) = 3: f(3/1) = 3/3 = 1 = a(1);
A058972(2) = 9: f(9/1) = 8/4 = 2 = a(2);
A058972(3) = 15: f(15/1) = 15/5 = 3 = a(3);
A058972(4) = 24: f(24/1) = 6/3 = 2 = a(4).

Prog

(PARI) f2(p, q) = (sigma(p+q)-p-q)/numdiv(p+q);
f1(r) = f2(numerator(r), denominator(r));
loop(list) = {my(v=Vecrev(list)); for (i=2, #v, if (v[i] == v[1], return(1)); ); }
ff(n) = {my(ok=0, m=f2(n, 1), list=List()); while(denominator(m) != 1, m = f1(m); listput(list, m); if (loop(list), return (0)); ); return(m); }
lista(nn) = {for (n=1, nn, my(x=ff(n)); if (x, print1(x, ", ")); ); } \\ Michel Marcus, Feb 09 2022

Crossrefs

Cf. A058972.

Sequence in context: A365049 A297162 A322587 * A155520 A365784 A235912

Adjacent sequences: A058970 A058971 A058972 * A058974 A058975 A058976

Keyword

nonn,easy

Author

N. J. A. Sloane, Jan 14 2001

Extensions

Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 22 2003

Status

approved