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A078493 One-prime decades. 0
90, 110, 120, 140, 180, 210, 240, 290, 300, 360, 390, 410, 420, 450, 470, 480, 550, 580, 630, 660, 680, 690, 710, 720, 740, 770, 780, 790, 800, 810, 830, 860, 870, 900, 920, 930, 950, 960, 980, 1000, 1020, 1040, 1050, 1080, 1110, 1160, 1170, 1190, 1200, 1240 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

The year 2003 is the only prime year in the 2000 decade.

LINKS

Table of n, a(n) for n=0..49.

MATHEMATICA

Select[10*Range[200], PrimePi[#+10]-PrimePi[#]==1&] (* Harvey P. Dale, Apr 13 2020 *)

PROG

(PARI) decade1(n1, n2) = { forstep(x=n1, n2, 10, if(isprime(x+1) && !isprime(x+3) && !isprime(x+7) && !isprime(x+9), print1(x" "); ); if(isprime(x+3) && !isprime(x+1) && !isprime(x+7) && !isprime(x+9), print1(x" "); ); if(isprime(x+7) && !isprime(x+1) && !isprime(x+3) && !isprime(x+9), print1(x" "); ); if(isprime(x+9) && !isprime(x+1) && !isprime(x+3) && !isprime(x+7), print1(x" "); ); ); }

CROSSREFS

Sequence in context: A043224 A039401 A044004 * A176683 A135197 A025371

Adjacent sequences:  A078490 A078491 A078492 * A078494 A078495 A078496

KEYWORD

easy,nonn,base

AUTHOR

Cino Hilliard, Jan 04 2003

STATUS

approved

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Last modified June 19 18:24 EDT 2021. Contains 345144 sequences. (Running on oeis4.)