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A280895 For any n>=0, least prime k = p^d-2*n, where p is a prime and d is its number of digits. 1
2, 3, 3, 163, 113, 1030291, 109, 107, 2571337, 103, 101, 2248069, 97, 263, 1442869, 139, 89, 1225009, 2685583, 83, 2571313, 79, 317, 2571307, 73, 71, 1224991, 67, 113, 3307891, 61, 59, 104633567005988371387, 103, 53, 1224973, 97, 47, 1224967, 43, 41, 1030219, 37 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Paolo P. Lava, Table of n, a(n) for n = 0..1000

EXAMPLE

a(5) = 1030291 because 1030291 is the least prime such that 101^3 - 2*5 = 1030301 - 10 = 1030291.

MAPLE

P:=proc(q) local a, b, k, n; for n from 0 to q do for k from 1 to q do a:=ithprime(k);

b:=a^(ilog10(a)+1)-2*n; if isprime(b) then lprint(n, b); break; fi; od; od; end: P(1000);

CROSSREFS

Cf. A055642, A280427

Sequence in context: A242786 A214219 A323340 * A088266 A116889 A037847

Adjacent sequences:  A280892 A280893 A280894 * A280896 A280897 A280898

KEYWORD

nonn,base

AUTHOR

Paolo P. Lava, Jan 10 2017

STATUS

approved

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Last modified August 11 15:12 EDT 2020. Contains 336428 sequences. (Running on oeis4.)