A232235 - OEIS

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A232235

Primes that can be written in binary representation as concatenation of two primes: p and p-2. That is, primes representable as p * 2^L + p-2, where p and p-2 are primes, and L is the length of binary representation of p-2: L = A070939(p-2).

23, 61, 1021, 139021, 145177, 222127, 2645257, 2706727, 2928019, 3050959, 3997597, 38695537, 45086077, 49903561, 50247667, 53688727, 56294101, 545636617, 556450387, 558023299, 563331877, 563921719, 581616979, 582993277, 607570027, 619956709, 638045197, 660262579

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OFFSET

1,1

COMMENTS

A subsequence of A232085.

LINKS

Table of n, a(n) for n=1..28.

FORMULA

a(n) = A232237(n) * 2^A070939(A232237(n)-2) + A232237(n)-2.

CROSSREFS

Cf. A000040, A070939, A232085.

Sequence in context: A067194 A355984 A355985 * A107692 A089823 A304896

Adjacent sequences: A232232 A232233 A232234 * A232236 A232237 A232238

KEYWORD

nonn,base,less

AUTHOR

Alex Ratushnyak, Nov 20 2013

STATUS

approved