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A102655 Numbers that are the arithmetic mean of four successive primes. 8
9, 12, 15, 18, 22, 30, 38, 42, 46, 55, 60, 68, 81, 87, 102, 105, 108, 114, 120, 127, 139, 144, 149, 155, 165, 175, 181, 186, 195, 200, 215, 228, 232, 241, 247, 253, 260, 265, 270, 278, 291, 306, 312, 318, 333, 341, 352, 357, 363, 381, 387, 399, 420, 426, 431 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..55.

FORMULA

4*n = A000040(i) + A000040(i+1) + A000040(i+2) + A000040(i+3) for some i>=1.

EXAMPLE

a(1) = 9 because (5+7+11+13)/4=9;

a(2) = 12 because (7+11+13+17)/4=12;

a(3) = 15 because (11+13+17+19)/4=15.

MATHEMATICA

Select[ Table[ Sum[ Prime[i], {i, n, n + 3}]/4, {n, 83}], IntegerQ[ # ] &] (* Robert G. Wilson v, Feb 04 2005 *)

Select[MovingAverage[Prime[Range[500]], 4], IntegerQ] (* Harvey P. Dale, Aug 10 2012 *)

CROSSREFS

Cf. A034963.

Sequence in context: A235341 A342082 A161345 * A308748 A120167 A263674

Adjacent sequences:  A102652 A102653 A102654 * A102656 A102657 A102658

KEYWORD

easy,nonn

AUTHOR

Giovanni Teofilatto, Feb 02 2005

EXTENSIONS

Edited by Robert G. Wilson v and W. Neville Holmes, Feb 04 2005

STATUS

approved

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Last modified April 15 02:27 EDT 2021. Contains 342974 sequences. (Running on oeis4.)