A079049 Recamán variation: a(1) = 1; for n > 1, a(n) = a(n-1)-prime(n) if that number is positive and not already in the sequence, otherwise a(n) = a(n-1)+prime(n).

1, 4, 9, 2, 13, 26, 43, 24, 47, 18, 49, 12, 53, 10, 57, 110, 51, 112, 45, 116, 189, 268, 185, 96, 193, 92, 195, 88, 197, 84, 211, 80, 217, 78, 227, 76, 233, 70, 237, 64, 243, 62, 253, 60, 257, 58, 269, 46, 273, 44, 277, 38, 279, 28, 285, 22, 291, 20, 297, 16, 299, 6, 313

Offset

1,2

Links

Table of n, a(n) for n=1..63.

Prog

(PARI) an=vector(100); an[1]=1; a(n)=if(n<0, 0, an[n]); an[n]=if(abs(sign(a(n-1)-prime(n))-1)+setsearch(Set(vector(n-1, i, a(i))), a(n-1)-prime(n)), a(n-1)+prime(n), a(n-1)-prime(n))

Crossrefs

Cf. A005132.

Sequence in context: A238324 A370952 A128204 * A366908 A114578 A135044

Adjacent sequences: A079046 A079047 A079048 * A079050 A079051 A079052

Keyword

nonn

Author

Benoit Cloitre, Feb 02 2003

Status

approved