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 A088935 Numbers n such that leading digits of 2^n and 5^n are equal. 2
 0, 5, 15, 78, 88, 98, 108, 118, 181, 191, 201, 211, 274, 284, 294, 304, 367, 377, 387, 397, 407, 470, 480, 490, 500, 563, 573, 583, 593, 603, 666, 676, 686, 696, 759, 769, 779, 789, 852, 862, 872, 882, 892, 955, 965, 975, 985 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS David A. Corneth, Table of n, a(n) for n = 1..10000 T. Sillke, Powers of 2 and 5 Puzzle EXAMPLE 78 is in the sequence since 2^78 = 302231454903657293676544 and 5^78 = 3308722450212110699485634768279851414263248443603515625 98 is in the sequence since 2^98 = 316912650057057350374175801344 and 5^98 = 315544362088404722164691426113114491869282574043609201908111572265625. MAPLE filter:= n -> convert(2^n, base, 10)[-1]=convert(5^n, base, 10)[-1]: select(filter, [\$0..1000]); # Robert Israel, Aug 09 2018 MATHEMATICA Select[ Range[ 1000 ], IntegerDigits[ 2^# ][ [ 1 ] ] == IntegerDigits[ 5^# ][ [ 1 ] ] & ] PROG (PARI) is(n)=(digits(2^n)[1]==digits(5^n)[1]); for(n=0, 10^3, if(is(n), print1(n, ", "))); \\ Joerg Arndt, Aug 10 2018 CROSSREFS Cf. A088995. Sequence in context: A032122 A220818 A064678 * A183937 A275971 A030487 Adjacent sequences:  A088932 A088933 A088934 * A088936 A088937 A088938 KEYWORD base,nonn AUTHOR Lekraj Beedassy, Dec 01 2003 EXTENSIONS Edited by Robert G. Wilson v, Dec 02 2003 STATUS approved

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Last modified September 20 02:21 EDT 2020. Contains 337261 sequences. (Running on oeis4.)