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A131535
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Least power of 2 having exactly n consecutive 1's in its decimal representation.
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1
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4, 40, 42, 313, 485, 1841, 8923, 8554, 81783, 165742, 1371683, 1727601
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OFFSET
| 1,1
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EXAMPLE
| a(3)=42 because 2^42(i.e. 4398046511104) is the smallest power of 2 to contain a run of 3 consecutive ones in its decimal form.
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MATHEMATICA
| a = ""; Do[ a = StringJoin[a, "1"]; b = StringJoin[a, "1"]; k = 1; While[ StringPosition[ ToString[2^k], a] == {} || StringPosition[ ToString[2^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]
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CROSSREFS
| Sequence in context: A049475 A080271 A104292 * A077329 A169967 A061473
Adjacent sequences: A131532 A131533 A131534 * A131536 A131537 A131538
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KEYWORD
| more,nonn,base
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AUTHOR
| Shyam Sunder Gupta (guptass(AT)rediffmail.com), Aug 26 2007
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EXTENSIONS
| 2 more terms from Sean A. Irvine (sairvin(AT)xtra.co.nz), Jul 19 2010
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