A131697 Prime averages of two successive perfect prime powers.

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, 5336101, 6200269, 6502501, 7177693, 7209229

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..1000

Example

101 is the average of 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. A000961, A075455 (Prime averages of two successive perfect powers).

Sequence in context: A142692 A060012 A142507 * A153806 A227521 A364147

Adjacent sequences: A131694 A131695 A131696 * A131698 A131699 A131700

Keyword

nonn

Author

Tanya Khovanova, Sep 15 2007

Extensions

More terms from Amiram Eldar, Feb 18 2022

Status

approved