A161177 Index of first multiple of n-th prime in A005179.

2, 4, 12, 32, 96, 240, 640, 1280, 2560, 9600, 19200, 57344, 114688, 229376, 458752

Offset

1,1

Comments

The numbers are divisible by higher and higher powers of 2 because the numbers in A005179 typically have a "tail" of primes occurring in first power only.

Links

Table of n, a(n) for n=1..15.

Example

a(3)=12: The third prime is 5 and A005179(12)=60 is the first multiple of 5 occurring in sequence A005179.

Prog

(PARI) a(n) = my(p=prime(n), k=1); while (A005179(k) % p, k++); k; \\ Michel Marcus, Apr 20 2024

Crossrefs

Cf. A005179.

Sequence in context: A025178 A231295 A087211 * A039721 A148193 A341344

Adjacent sequences: A161174 A161175 A161176 * A161178 A161179 A161180

Keyword

nonn,hard,more,changed

Author

Hagen von Eitzen, Jun 05 2009

Extensions

a(13)-a(15) from Michel Marcus, Apr 20 2024

Status

approved