A019990 Indices n such that A307672(2*n) = 2.

1, 3, 4, 7, 9, 11, 12, 13, 19, 21, 22, 25, 27, 29, 32, 33, 34, 36, 38, 39, 40, 46, 55, 57, 58, 61, 63, 65, 66, 67, 73, 75, 76, 79, 81, 83, 86, 87, 89, 95, 96, 97, 99, 101, 102, 103, 106, 108, 110, 113, 114, 115, 117, 119, 120, 121, 127, 136, 138, 139, 145

Offset: 0

Author

Bill Gosper

Keywords

• nonn

Comments

The original definition was: "A threequence, a 3-way partitioning of the integers: define a,b,c,A,B,C by a(0)=true, b(0)=c(0)=A(0)=B(0)=C(0)=false, a(n)=a(m) OR C(m) OR B(m), b(n)= b(m) OR A(m) OR C(m), c(n)= c(m) OR B(m) OR A(m), A(n)= A(m) OR b(m) OR c(m), B(n)= B(m) OR c(m) OR a(m), C(n)= C(m) OR a(m) OR b(m), where m = [ (n+1)/3 ]; sequence gives n such that b(2n) is true." - Sean A. Irvine, Apr 30 2019

Links

• R. W. Gosper, J. Z. Hunts, Strange Series for Sierpinski’s Gasket, G4G10 Exchange Book, Vol. 2 (2012), 59-60.

Crossrefs

Cf. A019989, A019991, A307672.

Extensions

New name from Sean A. Irvine, Apr 30 2019