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 A131552 Least positive power of 3 having exactly n consecutive 1's in its decimal representation. 2
 4, 19, 93, 334, 841, 3404, 7271, 7720, 44152, 406774, 993948, 2421339, 8786439, 11387707 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS No more terms < 2*10^7. LINKS EXAMPLE a(3)=93 because 3^93 (i.e., 235655016338368235499067731945871638181119123) is the smallest power of 3 to contain a run of 3 consecutive ones in its decimal form. MATHEMATICA a = ""; Do[ a = StringJoin[a, "1"]; b = StringJoin[a, "1"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {} || StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ] PROG (Python) def A131552(n): ....m, s = 1, '1'*n ....for i in range(1, 10**9): ........m *= 3 ........if s in str(m): ............return i ....return "search limit reached." # Chai Wah Wu, Dec 11 2014 CROSSREFS Sequence in context: A181950 A288687 A275751 * A122369 A005978 A083065 Adjacent sequences:  A131549 A131550 A131551 * A131553 A131554 A131555 KEYWORD more,nonn,base AUTHOR Shyam Sunder Gupta, Aug 26 2007 EXTENSIONS a(11)-a(14) from Lars Blomberg, Feb 02 2013 Definition edited by Chai Wah Wu, Dec 11 2014 STATUS approved

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Last modified December 15 13:27 EST 2018. Contains 318149 sequences. (Running on oeis4.)