A070061 Least number of fecundity n (A070562).

0, 5, 25, 19, 23, 18, 9, 7, 4, 2, 1, 282, 1529, 1586, 1397, 898, 658, 538, 477, 529, 736, 586, 397, 366, 294, 246, 243, 187, 3237326, 3677393, 3586673, 3553787, 3515987, 22572473, 518376965, 516675965, 516963965, 41883474553, 41881554553, 41863638649, 35632297938395

Offset

0,2

Comments

a(41) > 2.75*10^14. - Giovanni Resta, Jun 04 2013

References

P. Tougne, Jeux Mathematiques column, Pour La Science (French edition of "Scientific American"), Vol. 82, Aug. 1984, Prob. 6, pp. 101, 104.

Links

Table of n, a(n) for n=0..40.

Example

a(9)=2 since we have the 9-step chain 2 -> 4 -> 8 -> 16 -> 22 -> 26 -> 38 -> 62 -> 74 -> 102.

Mathematica

f[n_] := Length@ FixedPointList[ # + Times @@ IntegerDigits@# &, n] - 2; t = Table[0, {50}]; k = 1; While[k < 2300000001, a = f@k; If[ t[[a + 1]] == 0, t[[a + 1]] = k; Print[{k, a}]]; k++ ]; t (* Robert G. Wilson v, Jun 27 2010 *)

Crossrefs

Cf. A070562, A070257, A003001.

Sequence in context: A337392 A070377 A070383 * A070376 A036139 A070382

Adjacent sequences: A070058 A070059 A070060 * A070062 A070063 A070064

Keyword

base,hard,nonn

Author

Lekraj Beedassy, May 06 2002

Extensions

Corrected and extended by Jason Earls, May 26 2002

a(34)-a(36) from Robert G. Wilson v, Jun 27 2010

a(37)-a(40) from Giovanni Resta, Jun 04 2013

Status

approved