A038370 Smallest prime with "n^2" as central digit(s).

101, 113, 149, 191, 1163, 1259, 1361, 1493, 2647, 1811, 11003, 11213, 11443, 11699, 11969, 12251, 12569, 12893, 13241, 13613, 14009, 14411, 14843, 15299, 15761, 16253, 16763, 17291, 27847, 18413, 19001, 29611, 210241, 110899, 311561, 112253, 112967

Offset

0,1

Comments

See also A084413, A084414.

1195 is the smallest n such that 2 digits are needed on both sides of 1195^2 = 1428025 to give prime 10142802503. - Michel Marcus, Jun 05 2013

Links

Table of n, a(n) for n=0..36.

Prog

(PARI) a(n) = {a = 1; ok = 0; while (!ok, lena = #Str(a); lenn = #Str(n^2); for (b=0, 10^lena - 1, p = b + 10^lena*n^2 + 10^(lenn+lena)*a; if (isprime(p), return (p)); ); a++; ); } \\ Michel Marcus, Jun 05 2013

Crossrefs

Cf. A084413, A084414.

Sequence in context: A084414 A164937 A105992 * A084430 A182693 A328996

Adjacent sequences: A038367 A038368 A038369 * A038371 A038372 A038373

Keyword

easy,nonn,base

Author

Zak Seidov, Jun 25 2003

Extensions

Corrected by Robert G. Wilson v, Jun 27 2003

a(19) corrected by Sean A. Irvine, Jan 12 2021

Status

approved