

A355897


a(n) = index in A354790 of first nonprime term divisible by prime(n).


2



7, 7, 14, 14, 15, 17, 29, 64, 71, 79, 119, 120, 127, 223, 239, 260, 287, 288, 319, 320, 447, 484, 511, 512, 519, 960, 967, 968, 969, 1044, 1151, 1152, 1155, 1156, 1279, 1280, 1283, 1387, 1791, 1792, 1919, 1920, 1921, 2048, 2051, 2052, 2079, 3872, 3875, 3876, 3879, 3880, 4095, 4096
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OFFSET

1,1


LINKS

N. J. A. Sloane, Table of n, a(n) for n = 1..236


EXAMPLE

The first few nonprime terms in B = A354790, and their prime factors are:
n B(n)=p*q p pi(p) q pi(q)
7, 6, 2, 1, 3, 2
14, 35, 5, 3, 7, 4
15, 22, 2, 1, 11, 5
17, 39, 3, 2, 13, 6
29, 85, 5, 3, 17, 7
31, 14, 2, 1, 7, 4
35, 33, 3, 2, 11, 5
B(14) = A354790(14) = 35 = 5*7 is the first nonprime term divisible by 5 = prime(3), therefore a(3) = 14.


CROSSREFS

Cf. A354790, A354791, A354792.
Sequence in context: A173314 A040043 A339706 * A003872 A168374 A112438
Adjacent sequences: A355894 A355895 A355896 * A355898 A355899 A355900


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Aug 28 2022


STATUS

approved



