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A152652 Least prime p with digit sum A047235(n). 1
2, 13, 17, 19, 59, 79, 389, 499, 1889, 1999, 6899, 17989, 39989, 49999, 98999, 199999, 599999, 799999, 2999999, 4999999, 9899999, 19999999, 59999999, 189997999, 389999999, 689899999, 998999999, 2999899999, 6999999989, 9899989999, 39899999999, 68899999999, 98999999999 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

David A. Corneth, Table of n, a(n) for n = 1..1713

FORMULA

{min A000040(i): A007605(i) = A047234(n)}. - R. J. Mathar, Dec 12 2008

PROG

(MAGMA) T:=[ n eq 1 select 2 else Self(n-1)+2*(1+n mod 2): n in [1..22] ]; S:=[]; p:=2; for k in T do while &+Intseq(p, 10) ne k do p:=NextPrime(p); end while; Append(~S, p); end for; S; // Klaus Brockhaus, Dec 13 2008

(PARI) a(n) = {n = (n-1)\2*6+3+(-1)^n ; t = ceil(n/9); leastfound = oo; while(leastfound == oo, my(p = partitions(n, [1, 9], [t, t])); v = vector(#p, i, oo); for(i = 1, #p, if(fromdigits(Vec(p[i])) > leastfound, next(2)); forperm(Vec(p[i]), q, if(isprime(fromdigits(Vec(q))), leastfound = min(leastfound, fromdigits(Vec(q))); v[i] = min(v[i], fromdigits(Vec(q))); next(2); ) ) ); t++ ); leastfound }\\ David A. Corneth, Jun 13 2020

CROSSREFS

Cf. A111380 (smallest prime whose digital sum is equal to the n-th composite number not congruent to 0 (modulo 3)). - Klaus Brockhaus, Dec 12 2008

Cf. A000040, A007605, A047234, A047235.

Sequence in context: A153507 A124277 A038889 * A142339 A105913 A020480

Adjacent sequences:  A152649 A152650 A152651 * A152653 A152654 A152655

KEYWORD

nonn,base

AUTHOR

Giovanni Teofilatto, Dec 10 2008

EXTENSIONS

Edited and extended by R. J. Mathar, Dec 12 2008

a(20)-a(22) from Klaus Brockhaus, Dec 13 2008

More terms from Jinyuan Wang, Jun 13 2020

STATUS

approved

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Last modified August 4 09:03 EDT 2020. Contains 336201 sequences. (Running on oeis4.)