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A226178 Exponents n such that 2^n - previous_prime(2^n) = next_prime(2^n) - 2^n. 0
2, 6, 12, 76, 181, 1099, 1820 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The differences next_prime(2^n) - 2^n are respectively: 1, 3, 3, 15, 165, 1035, 663.

LINKS

Table of n, a(n) for n=1..7.

EXAMPLE

2^6 = 64, next prime = 67, previous prime = 61, 67-64 = 64-61 = 3, hence 6 is in the sequence.

MATHEMATICA

Reap[Do[m = 2^n; p = NextPrime[m, -1]; q = NextPrime[m]; If[p + q == 2*m, Print[n]; Sow[n]], {n, 2, 10^4}]][[2, 1]]

PROG

(PARI) isok(n) = my(p=2^n); p-precprime(p-1) == nextprime(p+1) - p; \\ Michel Marcus, Oct 02 2019

CROSSREFS

Cf. A000079, A014210, A014234, A117387, A145025.

Sequence in context: A107763 A166470 A144144 * A129085 A274941 A141288

Adjacent sequences:  A226175 A226176 A226177 * A226179 A226180 A226181

KEYWORD

nonn,more

AUTHOR

Jean-Fran├žois Alcover, May 30 2013

EXTENSIONS

Offset 1 from Michel Marcus, Oct 02 2019

STATUS

approved

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Last modified January 21 03:16 EST 2021. Contains 340332 sequences. (Running on oeis4.)