A119990 a(1) = 1. a(n) = sum of the earlier terms of the sequence, a(k), where GCD(n,a(k)) is <= k, for 1 <= k <= n-1.

1, 1, 2, 4, 8, 16, 32, 8, 72, 144, 288, 72, 648, 1296, 2592, 808, 5992, 6872, 18856, 37712, 75424, 150848, 301696, 598224, 1201616, 1201616, 3600312, 7199168, 14404328, 28808656, 57617312, 49885800, 164522200, 329642624, 659285248

Offset

1,3

Links

Table of n, a(n) for n=1..35.

Example

GCD(8,a(k)), for those a(k)'s where 1 <= k <= 7, is {1,1,2,4,8,8,8}.
Of these GCD's, each but the 8's is <= k. So a(8) = 1+1+2+4 = 8.

Prog

(PARI) {m=36; print1(a=1, ", "); v=[a]; for(n=2, m, a=0; for(k=1, n-1, if(gcd(n, v[k])<=k, a=a+v[k])); print1(a, ", "); v=concat(v, a))} - (Klaus Brockhaus, Aug 15 2006)

Crossrefs

Sequence in context: A016020 A364628 A328753 * A036128 A073477 A220105

Adjacent sequences: A119987 A119988 A119989 * A119991 A119992 A119993

Keyword

nonn

Author

Leroy Quet, Aug 03 2006

Extensions

Corrected and extended by Klaus Brockhaus, Aug 15 2006

Status

approved