A261543 - OEIS

A261543

Numbers of the form (prime(k) + Fibonacci(k))/2.

2, 5, 8, 15, 20, 42, 60, 137, 210, 520, 828, 2124, 3418, 8895, 14370, 37561, 60747, 158959, 257169, 673198, 1089220, 2851513, 4613807, 12078987, 19544166, 51167164, 82790160, 216747314, 350704463, 918156051, 1485607642, 3889371138, 6293134627

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OFFSET

1,1

COMMENTS

The numbers represented as the arithmetic mean of the Fibonacci numbers and prime numbers with identical indices.

LINKS

Table of n, a(n) for n=1..33.

Eric Weisstein's World of Mathematics, Prime Number

Eric Weisstein's World of Mathematics, Fibonacci Number

FORMULA

a(n) = (prime(A001651(n + 1)) + Fibonacci(A001651(n + 1)))/2

EXAMPLE

a(1) = (prime(2) + Fibonacci(2))/2 = (3 + 1)/2 = 2.

MATHEMATICA

Select[Array[(Prime[#] + Fibonacci@ #)/2 &, 50], IntegerQ] (* Michael De Vlieger, Aug 24 2015 *)

PROG

(PARI) a(n)=n+=n\2+1; (prime(n)+fibonacci(n))/2 \\ Charles R Greathouse IV, Aug 24 2015

CROSSREFS

Cf. A000040, A000045, A004397, A001651.

Sequence in context: A090980 A329603 A309546 * A307190 A183409 A262867

Adjacent sequences: A261540 A261541 A261542 * A261544 A261545 A261546

KEYWORD

nonn,easy

AUTHOR

Ilya Gutkovskiy, Aug 24 2015

STATUS

approved