

A019990


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


3



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
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OFFSET

0,2


COMMENTS

The original definition was: "A threequence, a 3way 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

Table of n, a(n) for n=0..60.
R. W. Gosper, J. Z. Hunts, Strange Series for Sierpinskiâ€™s Gasket, G4G10 Exchange Book, Vol. 2 (2012), 5960.


CROSSREFS

Cf. A019989, A019991, A307672.
Sequence in context: A274794 A115104 A095043 * A288634 A284776 A047544
Adjacent sequences: A019987 A019988 A019989 * A019991 A019992 A019993


KEYWORD

nonn


AUTHOR

Bill Gosper


EXTENSIONS

New name from Sean A. Irvine, Apr 30 2019


STATUS

approved



