A060031 Katydid sequence: closed under n -> 2n + 2 and 7n + 7.

1, 4, 10, 14, 22, 30, 35, 46, 62, 72, 77, 94, 105, 126, 146, 156, 161, 190, 212, 217, 252, 254, 294, 314, 324, 329, 382, 426, 436, 441, 506, 510, 511, 546, 590, 630, 650, 660, 665, 742, 766, 854, 874, 884, 889, 1014, 1022, 1024, 1029, 1094, 1099, 1134, 1182

Offset

1,2

Comments

The first term that occurs in two different ways is 1814526 = a(3555) = 2*a(2385) + 2 = 7*a(1170) + 7. - Robert Israel, May 11 2025

References

C. Pickover, Wonders of Numbers, Chap. 67 Katydid sequences, Oxford University Press, NY 2001, p. 164-165.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

C. A. Pickover, "Wonders of Numbers, Adventures in Mathematics, Mind and Meaning," Zentralblatt review

Maple

with(priqueue):
initialize(pq);
insert([-1], pq);
R:= NULL: count:= 0:
while count < 100 do
  v:= -op(extract(pq));
  if v = w then next fi;
  R:= R, v;
w:= v;
  count:= count+1;
  insert([-(2*v+2)], pq);
  insert([-(7*v+7)], pq);
od:
R; # Robert Israel, May 11 2025

Crossrefs

Cf. A007319.

Sequence in context: A176551 A175731 A242486 * A112825 A051741 A022382

Adjacent sequences: A060028 A060029 A060030 * A060032 A060033 A060034

Keyword

nonn

Author

Jason Earls, Mar 17 2001

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Apr 20 2001

Status

approved