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A160668 Distance between prime(n) and the next higher power of 10. 4
8, 7, 5, 3, 89, 87, 83, 81, 77, 71, 69, 63, 59, 57, 53, 47, 41, 39, 33, 29, 27, 21, 17, 11, 3, 899, 897, 893, 891, 887, 873, 869, 863, 861, 851, 849, 843, 837, 833, 827, 821, 819, 809, 807, 803, 801, 789, 777, 773, 771, 767, 761, 759, 749, 743, 737, 731, 729, 723 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

FORMULA

From Alois P. Heinz, Dec 08 2017: (Start)

a(n) = 10^A055642(A000040(n)) - A000040(n).

a(n) = A228628(n) + 1 = A061601(A000040(n)) + 1. (End)

EXAMPLE

a(1)=8 because 10^1=10, and 10-2, 1st prime 2, = 8;

a(5)=89 because 10^2=100 and 100-11, 5th prime 11, = 89.

MAPLE

a:= n-> (p-> 10^length(p)-p)(ithprime(n)):

seq(a(n), n=1..100);  # Alois P. Heinz, Dec 08 2017

MATHEMATICA

Table[10^Ceiling[Log[Prime[n]]/Log[10]] - Prime[n], {n, 1, 100}] (* G. C. Greubel, May 02 2018 *)

PROG

(UBASIC)

20 N=3:print N:C=2

30 A=3:S=sqrt(N)

40 B=N/A 50 if A*B=int(N) then 70

60 A=A+2:if A<S then 40

70 if N=prmdiv(N) then print N; :else 130

80 if alen(N)=1 then print 10^1-N; :P=prmdiv(10^1-N):goto 120

90 if alen(N)=2 then print 10^2-N; :P=prmdiv(10^2-N):goto 120

100 if alen(N)=3 then print 10^3-N; :P=prmdiv(10^3-N):goto 120

110 if alen(N)=4 then print 10^4-N; :P=prmdiv(10^4-N)

120 print P; C:C=C+1:stop

130 N=N+2:S=sqrt(N):goto 40

140 'recipseq, Enoch Haga, May 22 2009

(PARI) a(n) = 10^ceil(log(prime(n))/log(10)) - prime(n); \\ Michel Marcus, Dec 08 2017

(MAGMA) [10^(Ceiling(Log(NthPrime(n))/Log(10))) - NthPrime(n): n in [1..30]]; // G. C. Greubel, May 02 2018

CROSSREFS

Cf. A000040, A055642, A061601, A160669, A160670, A228628.

Sequence in context: A316728 A231098 A072003 * A086033 A246504 A182527

Adjacent sequences:  A160665 A160666 A160667 * A160669 A160670 A160671

KEYWORD

easy,nonn,base

AUTHOR

Enoch Haga, May 23 2009

STATUS

approved

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Last modified November 13 15:41 EST 2019. Contains 329106 sequences. (Running on oeis4.)