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A145987 Prime subtrahends used in sequence under 10^n 1
5, 7, 11, 17, 29, 41, 47, 59, 71, 83, 89, 97, 113, 137, 173, 179, 191, 227, 239, 257, 281, 317, 347, 353, 359, 383, 401, 431, 443, 479, 491, 509, 521, 557, 569, 599, 617, 641, 647, 653, 683, 719, 743, 761, 773, 809, 821, 827, 863, 887, 911, 929, 941, 947, 953 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

A(13)=113 because 1000-113 = 887 and both 113 and 887 are prime.

PROG

(UBASIC) 10 'complementary primes under 10^n 20 N=3 30 A=3:S=sqrt(N) 40 B=N\A 50 if B*A=N then 140 60 A=A+2 70 if A<=S then 40 90 if N<10 then T=10-N:if T=prmdiv(T) then print T; N; 100 if N>=10 and N<100 then H=100-N:if H=prmdiv(H) then print H; N; 110 if N>=100 and N<1000 then U=1000-N:if U=prmdiv(U) then print U; N; 120 if N>=1000 and N<10000 then V=10000-N:if V=prmdiv(V) then print V; N 130 if N>10000 then stop 131 stop 140 N=N+2:goto 30

CROSSREFS

A145985

Sequence in context: A027690 A087200 A153118 * A060449 A046140 A023241

Adjacent sequences:  A145984 A145985 A145986 * A145988 A145989 A145990

KEYWORD

easy,nonn

AUTHOR

Enoch Haga, Oct 27 2008

STATUS

approved

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Last modified May 21 22:24 EDT 2019. Contains 323467 sequences. (Running on oeis4.)