A379960 Numbers k such that A276086(k)-1 or A276086(k)+1 is a perfect power (A001597), where A276086 is the primorial base exp-function.

1, 2, 4, 6, 7, 8, 13, 30, 34, 35, 36, 212, 214, 248, 254, 421, 2311, 2316, 2318, 2322, 2329, 2350, 2520, 2550, 2564, 2776, 4654, 5076, 9241, 30030, 30037, 30038, 30092, 30120, 30480, 32341, 32347, 32374, 34662, 60066, 510515, 510542, 510547, 510728, 510746, 512850, 512886, 515134, 540540, 540818, 542862, 542888, 1021442

Offset: 1

Author

Antti Karttunen, Jan 22 2025

Keywords

• nonn

Comments

Most terms seem to cluster after the primorials, A002110. (Compare also to the growth rate of A001597).

Examples

			See examples in A379961 and A379962.
		

Links

• Antti Karttunen, Table of n, a(n) for n = 1..122
• Index entries for sequences related to primorial base

Crossrefs

Cf. A001597, A002110, A276086.

Union of A379961 and A379962.

Cf. also A379963.

Programs

PARI

A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
is_A379960(n) = { my(x=A276086(n)); (1==(x-1) || ispower(x+1) || ispower(x-1)); };