40000000

Appears in sequences

• Powers of 2 written in base 8.at n=23A004647
• Powers of 2 written in base 16.at n=30A004655
• a(n)/10000000 gives sqrt(n) to 7 places.at n=15A027664
• Numbers k such that Sum_{j=1..k} d(j) is an integer where d(j) is the decimal fraction 0.2j (e.g., d(14) = 0.28).at n=12A054465
• Expansion of (1-6*x)/(1-10*x).at n=8A093141
• Erroneous version of A052218.at n=14A094628
• Expansion of (1+4x-6x^2-36x^3)/(1-19x^2+90x^4).at n=15A097112
• Lexicographically earliest increasing sequence whose k-th digit is the absolute difference between the two digits touching the k-th comma.at n=25A102663
• Numbers k such that the k-th triangular number contains only digits {0,2,8}.at n=14A119056
• a(3n)=10^n. a(3n+1)=4*10^n. a(3n+2)=7*10^n.at n=22A135262
• Numbers k such that k and k^2 use only the digits 0, 1, 4 and 6.at n=16A136859
• Numbers k such that k and k^2 use only the digits 0, 1, 4, 6 and 7.at n=41A136860
• Numbers k such that k^4 is sum of two positive 7th powers.at n=14A291830
• a(n) = phi(n^8) = n^7*phi(n).at n=9A306412
• Numbers k such that k and the k-th triangular number T(k) = k*(k+1)/2 have only even digits.at n=26A383939