A361505 Index of 2^n in A359804.

1, 2, 5, 10, 24, 38, 87, 172, 349, 706, 1407, 2752, 5487, 11103, 22285, 44429, 88993, 177746, 356460, 712129, 1425163, 2849424, 5701776, 11401709, 22804522, 45608572, 91219022, 182438457, 364879209, 729757797, 1459514883, 2919031155, 5838065175, 11676129412, 23352260426

Offset

0,2

Links

Table of n, a(n) for n=0..34.

Rémy Sigrist, C++ program

Mathematica

nn = 2^20; c[_] = False; q[_] = 1;
i = 1; j = 2; c[1] = c[2] = True; u = 3;
{1, 2}~Join~Reap[Monitor[Do[
     (k = q[#]; While[c[k #], k++]; k *= #;
        While[c[# q[#]], q[#]++]) &[(p = 2;
       While[Divisible[i j, p], p = NextPrime[p]]; p)];
     If[IntegerQ@ Log2[k], Sow[n]];
     Set[{c[k], i, j}, {True, j, k}];
If[k == u, While[c[u], u++]], {n, 3, nn}], n]][[-1, -1]] (* Michael De Vlieger, Mar 18 2023 *)

Prog

(C++) See Links section.

Crossrefs

Cf. A359804, A361502, A361504.

Sequence in context: A099963 A152784 A112855 * A299436 A049937 A026754

Adjacent sequences: A361502 A361503 A361504 * A361506 A361507 A361508

Keyword

nonn

Author

N. J. A. Sloane, Mar 18 2023

Extensions

a(26)-a(27) from Michael De Vlieger, Mar 19 2023

More terms from Rémy Sigrist, Mar 19 2023

Status

approved