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A105988 Near-repdigit semiprimes with 7 as repeated digit. 1
177, 377, 707, 717, 737, 767, 771, 778, 779, 3777, 4777, 5777, 7277, 7377, 7737, 7747, 7771, 7773, 7778, 7779, 7787, 7977, 8777, 9777, 17777, 37777, 57777, 70777, 77177, 77277, 77677, 77757, 77767, 77771, 277777, 577777, 677777, 707777, 737777 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

a(2)=377 is a term because 377 is a semiprime and all digits are equal to 7 except one.

MATHEMATICA

Rest[Flatten[Table[Select[FromDigits/@Flatten[Permutations/@Table[ PadRight[ {n}, k, 7], {n, 0, 9}], 1], PrimeOmega[#]==2&], {k, 3, 7}]]]//Union (* Harvey P. Dale, Jul 25 2020 *)

CROSSREFS

Sequence in context: A169641 A255786 A147028 * A292185 A083620 A097317

Adjacent sequences:  A105985 A105986 A105987 * A105989 A105990 A105991

KEYWORD

base,nonn

AUTHOR

Shyam Sunder Gupta, Apr 29 2005

STATUS

approved

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Last modified January 18 01:10 EST 2022. Contains 350410 sequences. (Running on oeis4.)