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A131697 Prime averages of two successive perfect prime powers. 0
101, 577, 677, 2203, 15877, 22501, 25609, 32401, 42061, 57601, 72901, 181501, 228211, 324901, 378229, 394393, 462409, 695581, 804709, 1664101, 1742401, 1971241, 2873029, 3062509, 3186229, 4137181, 4305661, 4347229, 4804889 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..29.

EXAMPLE

101 is the average between 81 and 121.

MATHEMATICA

a = Select[ Range[2, 10000000], ! PrimeQ[ # ] && Length[FactorInteger[ # ]] == 1 &]; sizea = Length[a]; (a[[Select[Range[sizea - 1], PrimeQ[(a[[ # ]] + a[[ # + 1]])/2] &]]] + a[[Select[Range[sizea - 1], PrimeQ[(a[[ # ]] + a[[ # + 1]])/2] &] + 1]])/2

CROSSREFS

Cf. A075455 - Prime averages of two successive perfect powers.

Sequence in context: A142692 A060012 A142507 * A153806 A227521 A171813

Adjacent sequences:  A131694 A131695 A131696 * A131698 A131699 A131700

KEYWORD

nonn

AUTHOR

Tanya Khovanova, Sep 15 2007

STATUS

approved

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Last modified December 16 01:14 EST 2018. Contains 318158 sequences. (Running on oeis4.)