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A213315 Numbers with exactly 8 nonprime substrings (substrings with leading zeros are considered to be nonprime). 1
1011, 1012, 1015, 1021, 1022, 1025, 1027, 1029, 1030, 1034, 1036, 1038, 1043, 1047, 1051, 1052, 1055, 1057, 1059, 1061, 1063, 1067, 1070, 1074, 1076, 1078, 1083, 1087, 1091, 1092, 1095, 1101, 1102, 1105, 1110, 1114 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sequence is finite. Proof: Each 8-digit number has at least 10 nonprime substrings. Thus, each number with more than 8 digits has >= 10 nonprime substrings, too. Consequently, there is a boundary b<10^7, such that all numbers > b have more than 8 nonprime substrings.

The first term is a(1)=1011=A213302(8). The last term is a(7483)=8313733=A213300(8).

LINKS

Hieronymus Fischer, Table of n, a(n) for n = 1..7483

EXAMPLE

a(1)=1011, since 1011 has 8 nonprime substrings (0, 1, 1, 1, 01, 10, 011, 1011).

a(7483)= 8313733 since there are 8 nonprime substrings (1, 8, 33, 831, 8313, 13733, 31373, 313733).

CROSSREFS

Cf. A019546, A035232, A039996, A046034, A069489, A085823, A211681, A211682, A211684, A211685.

Cf. A035244, A079307, A213300 - A213321.

Sequence in context: A317526 A235775 A262865 * A345906 A035125 A183849

Adjacent sequences:  A213312 A213313 A213314 * A213316 A213317 A213318

KEYWORD

nonn,fini,base

AUTHOR

Hieronymus Fischer, Aug 26 2012

STATUS

approved

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Last modified August 17 00:01 EDT 2022. Contains 356180 sequences. (Running on oeis4.)