A292379 Odd numbers k such that A292270((k-1)/2) is a square < ((k-1)/2)^2.

7, 15, 27, 31, 63, 95, 127, 255, 277, 305, 511, 519, 1023, 1921, 2047, 2349, 3575, 4095, 8191, 8743, 10525, 16383, 17955, 24661, 26585, 27305, 32767, 36611, 40677, 65535, 85173

Offset

1,1

Links

Table of n, a(n) for n=1..31.

Prog

(PARI)
A000265(n) = (n >> valuation(n, 2));
A006519(n) = 2^valuation(n, 2);
A292270(n) = { my(x = n+n+1, z = ((1+x)/A006519(1+x)), m = A000265(1+x));
while(m!=1, z += ((x+m)/A006519(x+m)); m = A000265(x+m)); z; };
n=1; k=0; while(k < 120, m = A292270(n); if(issquare(m) && (m < n^2), k++; write("b292379.txt", k, " ", 1+(2*n))); n++);

Crossrefs

Subsequence of A292939.

Doesn't contain any terms of A001122.

Cf. A000225 (subsequence from its term a(3) = 7 onward).

Cf. A292270.

Sequence in context: A012480 A226470 A063611 * A146624 A239934 A193553

Adjacent sequences: A292376 A292377 A292378 * A292380 A292381 A292382

Keyword

nonn,more

Author

Antti Karttunen and Vladimir Shevelev, Oct 06 2017

Status

approved