A175983 - OEIS

A175983

Squares n^2 that become prime after omitting all ones in their decimal expansion.

121, 1089, 11449, 21609, 31329, 56169, 117649, 127449, 131769, 139129, 142129, 154449, 178929, 199809, 431649, 471969, 751689, 1014049, 1159929, 1172889, 1194649, 1530169, 1841449, 2211169, 2411809, 2518569, 2634129, 3108169, 3143529

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OFFSET

1,1

COMMENTS

Corresponding values of n are 11, 33, 107, 147, 177, 237, 343, 357, 363, 373, 377, 393, 423, 447, 657, 687, 867, 1007, 1077, 1083, ....

The resulting primes are 2, 89, 449, 2609, 3329, 5669, 7649, 27449, 3769, 3929, 4229, 54449, 78929, 99809, 43649, 47969, 75689, ....

LINKS

Table of n, a(n) for n=1..29.

MATHEMATICA

Reap[Do[If[PrimeQ[FromDigits[DeleteCases[IntegerDigits[n^2], 1]]], Sow[n^2]], {n, 5000}]][[2, 1]]

PROG

(Magma) remove1:=func< n | [ d: d in n | d ne 1 ] >; [ s: n in [1..3400] | IsPrime(Seqint(remove1(Intseq(s)))) where s is n^2 ];

CROSSREFS

Sequence in context: A243810 A302561 A120353 * A307858 A329100 A208261

Adjacent sequences: A175980 A175981 A175982 * A175984 A175985 A175986

KEYWORD

nonn,base

AUTHOR

Zak Seidov, Dec 08 2010

STATUS

approved