A051276 Nonzero coefficients in one of the 5-adic expansions of sqrt(-1).

2, 1, 2, 1, 3, 4, 2, 3, 3, 2, 2, 4, 1, 3, 2, 4, 4, 3, 4, 4, 1, 2, 4, 1, 4, 1, 1, 3, 1, 4, 1, 4, 2, 1, 1, 3, 3, 2, 2, 4, 4, 2, 4, 3, 1, 2, 4, 3, 3, 3, 3, 1, 3, 1, 1, 3, 3, 4, 1, 3, 3, 3, 4, 2, 2, 2, 1, 4, 1, 1, 4, 4, 2, 1, 2, 3, 4, 4, 4, 2, 2, 1, 3, 1, 3, 2, 4, 2, 1, 4, 3, 4, 3, 1, 2, 1, 3, 3, 3, 1, 1, 3, 1, 2, 2

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy
• nice

Examples

			2 + 1*5 + 2*5^2 + 1*5^3 + 3*5^4 + 4*5^5 + 2*5^6 + 3*5^7 + 3*5^9 + 2*5^10 + 2*5^11 + 4*5^13 + 1*5^14 + 3*5^15 + 2*5^16 + 4*5^17 + 4*5^19 + ...
		

References

• Kurt Mahler, Introduction to p-adic numbers and their functions. Cambridge Tracts in Mathematics, 76. Cambridge University Press, Cambridge-New York, 1971. See pp. 35ff.

Crossrefs

Cf. A034935, A048898, A048899, A210850, A210851.

Programs

Maple

R:= select(t -> padic:-ratvaluep(t,1)=2,[padic:-rootp(x^2+1,5,200)]):
subs(0=NULL,op([1,1,3],R)); # Robert Israel, Mar 04 2016

PARI

sqrt(-1+O(5^100))

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)hotmail.com) and Jason Earls, Jun 15 2001

Name corrected by Robert Israel at the suggestion of Wolfdieter Lang, Mar 04 2016