A087458 - OEIS

A087458

Greatest prime p such that prime(n)+p <= prime(n+1); a(1)=1.

1, 2, 2, 3, 2, 3, 2, 3, 5, 2, 5, 3, 2, 3, 5, 5, 2, 5, 3, 2, 5, 3, 5, 7, 3, 2, 3, 2, 3, 13, 3, 5, 2, 7, 2, 5, 5, 3, 5, 5, 2, 7, 2, 3, 2, 11, 11, 3, 2, 3, 5, 2, 7, 5, 5, 5, 2, 5, 3, 2, 7, 13, 3, 2, 3, 13, 5, 7, 2, 3, 5, 7, 5, 5, 3, 5, 7, 3, 7, 7, 2, 7, 2, 5, 3, 5, 7, 3, 2, 3, 11, 7, 3, 7, 3, 5, 11, 2, 17

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OFFSET

1,2

COMMENTS

a(n) = A007917(A001223(n)) for n>1.

LINKS

Table of n, a(n) for n=1..99.

MATHEMATICA

Join[{1}, NextPrime[#+1, -1]&/@Differences[Prime[Range[2, 100]]]] (* Harvey P. Dale, Aug 04 2024 *)

CROSSREFS

Cf. A001223, A007917.

Sequence in context: A059964 A308050 A248147 * A052180 A065151 A345874

Adjacent sequences: A087455 A087456 A087457 * A087459 A087460 A087461

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Oct 23 2003

STATUS

approved